Pffft broken powers?! what about the confusing rules, Keywords and items, Vorpal falchions, stealth in combat, daggermaster warlocks, running while slowed and these are only the ones I've seen up on these boards
keywords and magic items: does the power get the keyword of the item its using (my thought long and short of it no, you do not turn a fireball into a firecold ball with an appropriate wand/staff/orb you just add the damage which said implement does)
Vorpal falchions: should they explode when any of the weapons D4 turn up 4 or only if both turn up 4? (rules as written only if both turn up, rules as intended its a new faster game I'd houserule with any individual dice turning up 4 explodes)
Stealth in combat: what prevents a rogue hiding behind a combat, sneak attacking, hiding with a minor movement (maybe even behind an ally) and then sneak attacking again, also whether the enemy of the rogue gets to roll his perception against the hide or just uses his passive ( I go with a roll for perception and the interpretation that once the enemy is aware of you you need to sneak attack from a different square)
Warlock daggermaster: multi class rogue and take daggermaster paragon path to gain among other things crit of 18-20 which apparently combines with the pact blade implement which can be a dagger and a warlock implement (I'd rule no way jose, a daggermaster is uber at slitting throats and vital spots with the business end of a dagger not increasing pact ranged powers still if the lock made a weapon attack with the pact blade the crit would be there)
Running while slowed: a move action is normally you move you speed, run is where you move your speed +2, slow a condition where your speed cannot increased above 2, question is is that +2 from run increasing your speed or just the squares moved (I rule squares moved) another question related to this is does slow take you to 2 movement then you apply more penalties like heavy armor, so if slowed and in chainmail you can only move 1 (I rule nope it only takes you to the +2 movement, one of the main reasons is that normally monsters -ve movement due to armor is not included in their stat blocks)