I made a half-orc slayer to use in a DnD 4E Neverwinter campaign. I got him all set up to use a longspear. The Spear Expertise feat adds damage on a charge, half-orcs' Swift Charge feature gives them +2 speed when they charge, and the Berserker's Charge Fighter stance gives +2 to speed and attack rolls when charging. Sounds fun: +11 to attack, 1d10 + 8 damage, and 9 speed on a charge at lvl 1.
Then I looked over the rest of the stuff you get as a Heroic Slayer, and I see that at lvl 7 you get a feature called Weapon Specialization. This feature grants extra controlling effects when you hit with Power Strike. If you're using a 2H Axe, you can knock the target prone. If you're using a 2H blade, you can slide each adjacent enemy 1 square. Wax Eagle pointed out that there's an additional Staff Specialization introduced in Dragon Magazine 391 which does your Dex modifier dmg to adjacent enemies.
Thing is: that's it. Those are the only weapon types listed. Regardless of whether other weapon groups are quality options or not, it seems ridiculous that a Slayer would be limited to using a weapon that qualifies as an Axe or Blade in order to get any benefit from one of their class features. Wizards improved this a bit by adding a staff expertise, but there are still multiple weapon groups not covered.
So the idea is to houserule an additional option for 2H spears.
It should be just like the others in that it triggers when you use Power Strike and that it imparts some sort of control effect or small damage.
It should also make sense, in the way that the current ones make sense. If I hit a guy with a big axe, it would make sense for him to fall over. If I make a big swing with my sword and hit real hard, it makes sense I might sweep some guys while I do it. Spears stab. If I stab someone real hard then... they're going to bleed?
Bleeding would be ongoing damage, but that's not a control effect and I'm not sure it would be balanced. Maybe it could cause a condition, like Weakened? With the staff expertise in mind, perhaps a little extra damage would be okay. Like ongoing Dex or something.
Maybe it's not bleeding. Maybe I stab them and can then push them around a little bit since I have my spear in their side. Perhaps I could push or slide the target 2 squares?
Maybe I can deal damage to an enemy adjacent to the target, like my spear pierced through and stabbed him too. That's not exactly control, but it does make sense.
Maybe they just grant combat advantage for a turn, I don't know.
The best answer will have an effect that makes sense in terms of the game world and is well balanced with the other options. If you feel a spear is underpowered compared to a greatsword or axe, then maybe it's a slightly stronger option, or vice-versa if you feel the opposite. Either way, justification would be great. You don't need to limit the effect to one I proposed in this question.
In addition, if anyone has ideas for other weapon groups that aren't covered, like Maces or Hammers, those would be useful as well.
For the future, it should be noted that Slayers get another feature at lvl 12 called Greater Weapon Specialization, which adds an Encounter Utility power associated with the weapon. I'll have to figure out one of these at some point as well, as this feature also only has options for Axes and Heavy Blades, with an additional staff option from Dragon Magazine.