Balanced, the existing feat is equally good
There are two distinct changes in your house-rule and I will deal with them separately.
Adding Ranger and Paladin as options
There is nothing about the ranger or paladin spells lists that make this inherently unbalanced for this feat. Each has a few unique spells, hunter's mark, hail of thorns, etc.. for the ...
My other answer discusses how this change effects the balance between the classes. In this answer I will focus on how it effects overall game balance and total party power level.
This increases party options but not power level
Ritual Casting is mostly a utility feature; since it requires 10 additional minutes of casting time, it is completely useless in ...
Very likely imbalanced
Paladins and Rangers are only partial spell casters. As such, they do not gain any spells until 2nd level. So this change would mean that this one feat is the same as taking two levels in either of these classes; at least in regards to spell casting abilities.
All of the other classes get their first spells their first level. So a ...
My other answer deals with how this change affects overall power level of the party and game balance. This answer focuses on how it alters the balance between the classes.
Rangers will love this. Slightly unbalanced.
Bard, Cleric, Druid and Wizard all already posses the Ritual Casting feature from 1st level. This house rule would have no benefit for them ...
Spells and Items
You will exclude a few edge cases, though it is arguable whether or not these could be used in an opportunity attack anyway.
The dismissal option of Dispel Evil and Good.
Using Flame Blade, Mordenkainen's Sword, or Vampiric Touch to attack.
This will have a major effect on some monsters, who will be unable to make ...
Balanced, only a few interactions will be impacted by this.
What you are proposing is a slight modification to the rules for casting at a higher level. RAW it reads (emphasis mine):
When a spellcaster casts a spell using a slot that is of a higher level than the spell, the spell assumes the higher level for that casting. For instance, if Umara casts ...
To quickly answer the opening question:
Any and all aspects he or she desires
Personally; for new players, i would go for Core rules only, anything else on case-by-case approval
The more sources you allow, the more chances for things to become complicated and unbalanced, and by making non-core options a "no unless i say so", you prevent problems like you ...
This rule modification negates most flanking situations except against Single or Huge+ creatures
This rule invalidates flanking for most situations against multiple combatants. Per the flanking rule in the DMG, if your ally is adjacent to a Medium creature then there is exactly one position that would fulfill the requirements of being "opposite". If this ...
Is my reading of the invisibility rules correct
Correct, they cannot see.
Is it "typical" for a DM to treat this as a downside of being invisible
Disclaimer: question is about typical use, so your (or my) experience may vary
Intro: As DM I typically run hardcore dark fantasy campaigns/one-shots with fights in Combat as War style and as much ...
You can't see yourself while invisible
As pointed out in the question, an invisible creature
is impossible to see without the aid of magic or a special sense
Spells only do what they say they do. The Invisibility spell does not grant any special sense. If it did, it would say so.
But this doesn't impose many penalties, under the rules
The other part ...
Can invisible creatures 1) see themselves and if not, 2) what are the consequences of that?
Thanks to @TimC, this appears to be a concise summary of what you are asking.
They answers are:
What it says in the invisible condition. These are:
it can't see itself,
it has an easier time hiding from itself (assuming this is ever going to come up),
it can ...