Mine (so far):
1) (Courtesy of Keterys)
The bonus to attack is not based on the primary ability score the power uses. Instead, the formula for any attack is as follows:
5 + 1/2 level + Weapon Proficiency
+1 at levels 5/11/15/21/25
Expertise feats are banned.
Damage still depends on the primary ability score of the power (thus a Cha based power still does +cha damage).
2)
Rel's use of Exploding Skills, Power Stunts and adjustment to Milestones.
3) Use a daily, it doesn't hit? You can opt to not expend the daily (and thus lose the action), but you do not gain the benefits of an Effect or Miss.
4) Battlerage Vigor is banned.
5) Careful Attack/Sure Strike. Add the following Text: Effect: You gain a +2 to the next attack you make.
6) Infernal Wrath's bonus damage is based on a mental stat of the player's choice.
7) Roll a 1 and you grant combat advantage until the beginning of your next turn.
8) If while stunned, you fail the save by 3 or less, you are instead dazed.
Rules currently under construction:
Solos and Conditions: A daze = loss of a move action, a Stun = loss of a standard action.
Magical items. I'm trying to think of a way to completely overhaul the magical item system. A way to make magical items more like artifacts. Likely I'll hand out a +1 at certain levels to all stats, and try to design some sort of items, but at the moment I just don't know.
Integrating Aspects (from Spirit of the Century) to D&D. Then linking Aspects to Action Points, and expanding the use of Action Points. This one I hesitate to do, because it might complicate matters and make it more of a muddled mess.