I have not made it to that late stage in the game that you are discussing, it sounds like dwarves are at a disadvantage there, but in the early to mid-game dwarves are easily the strongest race. Their units do the best at the void, crush the bosses easily, and their defense is by far the strongest thanks to snipers being about the only unit that can kill a Jacques before he wrecks the wall or sniping gold units before Elena can pull them back. This is one of the pro's/con's of the dwarf race for a while, they are strong in the early game but weak in the late game. So, although I do agree with adjusting dwarves so they stand a chance in the late game, I would also suggest nerfing their early game.
The advantage of being good vs bosses is sort of laughable. That is maybe relevant for 1 or 2 weeks, and with the loaning mechanic it really doesn't matter at all. (as someone mentioned, good for alts (lol) )
In terms of void, dwarf does well. But some timed ones are much easier to do with human units, unless you are very over leveled. And virion rez can make the flawless ones nearly as easy for humans. Again, with the loan feature for a few extra gold troops, this is only relevant for short periods of time anyways.
For very early game dwarf performs well, until research catches up to terrain bonuses and nobody ever fights off of grassland /desert ever again. Again, this amounts to being a very early game advantage, miners and mechs are made obsolete within months or weeks, depending on the speed of spending on the server. If someone believes otherwise based on previous (now dated) experience, I suggest you consider the patch changes I've highlighted for recently. My experience at early game as a dwarf back in july-august I would agree they had some serious advantages. On characters I've played more recently, not so much.
I have no problem with equalizing early game, maybe helping lich out and taking dwarf down a notch. At the end of the day though, it is a smaller consideration than playability going forward. It's difficult to describe the difference between a human's garrison being hospitalized, or losing a duel on enemy territory, vs dwarf experiencing the same thing. It is a severity of loss out of proportion at almost all points of time in the game that doesn't make sense.