Would these multi-classing house rules cause unintended problems?

Question

I'm part of an RPG Group that plays multiple campaigns in multiple systems. Lately, two of our members have announced interest in a D&D 5e campaign, which isn't a system this group has played before, although some of us have 3.5 experience.

Now our group has several members who prefer to be creative in building characters and find their own combinations of mechanics. However, 5e seems to have nerfed multi-classing to a significant degree, forcing Players to adhere to the predefined classes (which, to be fair, are better than they were in 3.5) unless they want to significantly weaken their characters. We have thus devised a few house rules we might implement to address this problem.

Unfortunately, none of us has enough experience with the system to properly judge their side effects. There are two effects that are not to be strongly considered:

1. The power level will rise slightly. This is obvious, to be expected and not a problem, unless the increase is a lot greater than we expect. Of course this may influence encounter design.
2. Intra-party balance will not be a huge consideration. We are an established group with good communication and cooperation. Unless there would be a truly massive new imbalance created, we probably won't notice.

Here are the rules:

• All classes that provide Extra Attack stack for the purposes of providing extra attacks up to the level they provide their last extra attack. (i.e. a Monk 2/Fighter 3 would have 2 attacks (because both Monk and Fighter gain Extra Attack at level 5 and they stack for 2+3=5) a Monk 2/Fighter 18 would have 4 (because the Monk stacks for up to 5 levels for 2+18=20 and the Fighter gains the 4th attack at Level 20) but a Monk 18/Fighter 2 would still only have 2 (because the Monk only gains one extra attack at Level 5 and thus only stacks up to there, and even a Fighter Level 7 (5+2) doesn't gain any more attacks than that)).
• The standard ability score improvement progression of 4th, 8th, 12th, 16th and 19th class level is based on character level instead. Additional ASIs such as the Fighter's are still attained at the listed class level.
• In addition to the multi-class proficiencies listed on page 164 PHB, the character gains proficiency in one skill from the class skill list of the newly adopted class.
• Instead of all the proficiencies gained when adopting a new class, including the additional skill proficiency above, the character may gain proficiency in one of the saves the new class is proficient in.

Issues I am anticipating:

• Wizard and Sorcerer dips don't have much to give up for a save and some magic. However, since full casters are still a lot more powerful than mundanes with a caster dip, that's probably not too bad. Everyone likes a few cantrips.
• Classes like Rogue and Bard are slightly devalued, because they lose the unique privilege of multi-class skill proficiencies. Not sure how serious of a problem this is or how to address it.
• Dipping in general becomes more viable, which is an intended outcome of these rules, but we'll have to see whether it goes out of hand. I hope that the loss of high level class features is enough of a threat to discourage exaggerated multi-dipping. The real goal is more to make 2-3 class combinations viable at lower levels.

So the main question remains: are there significant problems this would cause, mechanics this would break etc. that I as someone who doesn't know the 5e rule set terribly well am overlooking?

Answer 1

Multiclassing at lower levels will be extremely powerful but progression later may feel stunted and less satisfying.

You said:

• The standard ability score improvement progression of 4th, 8th, 12th, 16th and 19th class level is based on character level instead. Additional ASIs such as the Fighter's are still attained at the listed class level.

Untethering ASI's from class level and giving them out at character levels 4, 8 (etc.) will incentivise multiclassing at lower levels for obvious reasons - but the flip side of that is it'll also discourage single class characters. At class level four (hit dice aside) the ASI is the only thing that numerous classes get (Barbarian, Fighter, Paladin, Ranger, Rogue).

With your suggested change a Fighter 3 / Monk 1 has, apart from an extra hit dice, all of the capabilities of a Fighter 4 / Monk 1. If they do decide to take Fighter 4 (if they want to access high level Fighter class features) they'll effectively get nothing except HP for doing so.

Similarly, you said:

• All classes that provide Extra Attack stack for the purposes of providing extra attacks up to the level they provide their last extra attack.

This actually compounds the issue further. Our Fighter 3 / Monk 1 already has his ASI. While he won't get his normal class benefit from Fighter 4 - if he does take it he would now get Extra Attack early instead - problem solved! Except the problem's just been deferred because taking Fighter 5 has been similarly devalued... and in fact it's even worse than that.

Why would our Fighter 3 / Monk 1 take Fighter 4 for extra attack, when he could take Monk 2 and get all of the 2nd level monk features AND extra attack as well? In the short term it would be inefficient not to take Monk 2 instead. But now you've reduced Fighter 4 and Fighter 5 to both being HP only. But it's actually even worse still!

With the next two fighter levels being useless it's likely you'd push forward in Monk at level 6 with Fighter 3 and Monk 3. Great. But now you won't get much by way of improvement from Monk 4 or Monk 5 either! Sure you'll get an ASI when you reach character level 8 - but you'll get that regardless so in the short term it'll probably feel like it's better to multiclass even further.

Note: When they take class levels that have been stripped of rewards, these characters won't actually be worse off than someone who multiclasses using RAW rather than your house rules. But giving multi-classed characters class features like ASI's and Extra Attack early to help them 'keep pace' with single class characters will make later progression feel like much more of a slog.

Having the cool features early will be fun (and is probably pretty unbalanced - but as you're not too bothered about party balance I won't go into that), later on though, it will feel like the characters have practically plateaued in their development as they gain very little on certain level choices. All of the above problems will be repeated when you hit class level 8, 12 (etc.).

Basically, levelling will, in general, feel much less even (rather than a relatively smooth curve) and you could back yourself into a corner with what feels like no good choices to choose from.

Answer 2

Multiclassing becomes almost mandatory

Relevant differences between 3.5 and 5

Spellcasters are no longer significantly stronger than sword wielding warriors, and in some encounters clearly weaker. This has many reasons, the main ones are:

• Concentration severly limits the number of buffs/debuffs you can use simultaneously
• Spell save is tied to your proficiency bonus (character level) and your ability modifier
  • So having only 3rd level spells instead of 4th level ones does not make it more likely that an enemy succeeds on a save
• Caster level is only relevant for cantrips
  • So a Fireball cast by a 5th level Wizard causes the same damage as if it were cast by a 20th level one (assuming identical slots)

Cost-benefit

Even without your changes, starting with 1 level of Fighter on a Wizard gives you more and takes away less in 5e than in 3.5.
Beside the Con save, you get more hit points, a Fighting Style, access to better armor and shields, while your wizardness is delayed by one level.

With your changes, the ASIs are not delayed, so the benefit remains the same, while the cost goes down.

For non-full casters the benefits are even bigger, a Barbarian can have a much needed Fighting Style without delaying the two most important class features, ASIs and Extra Attack.

I already recommend 2 levels of Warlock for every Sorcerer and Bard to have a decent option when the enemy has too good saves, now it is even better.

You should not try to change something as a newbie

Multiclassing done right is powerful even now, it does not need to be stronger.

Answer 3

Dipping into Fighter becomes almost mandatory

With a Fighter multi class, if you allow ASI by character level and proficiency in one saving throw of that class, it allows ASI to be unaffected by multi classing (one of the intentional drawbacks of the feature) and a very powerful saving throw proficiency in Constitution. No spell caster class will want to be without one level in Fighter.

Not many classes gain access to more saving throw proficiency except for at higher levels, so allowing more than two early on is very overpowered especially for a Wizard who is going to heavily use that Con save to concentrate on their spells. I would remove this option here and just allow a skill to be selected instead.

In regards to ASI, a dip into Fighter would normally put the increase back by one level and would be something to consider. But your rule removes that, which would be an intended buff as you're looking for. Along with the extra attack ruling though, it massively improves Melee spell casters such as Paladins, War Clerics, Moon Druids, Hex Blade Warlocks etc.

Another thing, losing the option of high level class abilities isn't that much of a threat as most 5E campaigns don't go to a very high level. From my knowledge, most of the higher level games peter out at about levels 12-15. Make sure you consider high how you're players are going to get.