First of all, this thread is developing lots of posts way too long for me to bother reading them. So sorry in advance.
ok, lets settle this.
I hope we agree that if a dwarf with 16 strength and a Waraxe with dwarven weapon training (average damage 11.5) will benefit more from expertise than the 18 strength dragonborn with a longsword. (average damage 8.5) which is a realistic example.
Well first I'd like to point out that a waraxe with strength 16 and training equals 5.5+3+2=10.5, not 11.5
Then I should highlight the fact that you've given the dwarf an extra feat.
Then I'd like to suggest that a 16 strength dwarf is not very underpowered, and an 18 strength dragonborn could be more optimised yet.
However, I do agree that someone who does more damage, regardless of bonus to hit, gains more from expertise than someone who does less damage. I don't think less optimised characters do more damage though, rather the opposite.
A more fair version of your example might be strength 20 dragonborn with a bastard sword (average damage 10.5) vs your strength 16 dwarf with trainining (average damage 10.5). Both do equally well from expertise.
However weapon training is specific tom certain races, and becomes pointless at 15th level, when weapon focus is just as good, but for better weapons such as the longsword.
And i hope we agree, that expertise is superior to some other feats which appeared before...
but I believe, if nimble blade and expertise would swap places in PHB 1 and 2, noone had complained, most uf us would accept, that nimble blade is for those people who want to be even more specialised (and need combat advantage for powers and features)
I don't really agree- expertise is a bonus to hitm which stages over levels- this is clearly wrong, as it makes sense to maintain a constant bonus to hit as the levels go by. A heroic tier feat shouldn't get way better at paragon and epic tiers.
Also expertise is not a feat bonus- I probably would have missed this, but if I noticed, I would have assumed it was a mistake, and ruled it as a feat bonus (what possible reason is there for it not being a feat bonus.
Also, if they released further conditional +1 feats I would have laughed, and wondered what they were playing at.
So I agree we're in the same ballpark, but I'm yet to be convinced by your examples.