Whenever I see a feat that provides a +2 to damage, I laugh cynically and move on. I”m not usually a min-max type of player, but those feats are so utterly useless. +2 to damage is inconsequential even at 1st level, an even if the feat scales (+3 at 11th, etc.), it doesn’t help. Compared to a +2 to hit, which is a ten percent gain, a small damage bonus is a drop in the bucket. Some feats give a damage bonus equal to one of your ability modifiers, which can be nice in Heroic tier, but they don’t scale up very well.
My solution? Well, this isn’t carefully considered or playtested. I simply asked myself what damage bonus would make me at least look twice at those types of feats. +5. Any feat that would grant a +2 damage bonus should instead grant a +5 damage bonus. If a feat would scale up at higher levels, double the extra bonus. For example, a +2 bonus that goes to +3 at 11th level would give a +5 bonus, +7 at 11th level.
Another way to look at this is by comparing total damage output. If a +2 to hit causes you to hit 10 percent more often, a damage bonus taken in its place needs to make up the difference of all the lost damage for the attacks that missed. The math differs depending on your class, the specific attack, what weapon you’re using, etc., but beefing up those damage feats seems to make of the shortfall.
Does it seem like too much damage? No way. 4E combat takes too long as it is, and by the time you’re fighting enemies that regularly have two or three hundred HP, you’ll be desperate for anything to speed up the slog.