One thing that bothers me about the choice of the 21M top is that if you expect the whole world population to use bitcoins, then only very few people will be able to own even 1 BTC.
It would be better to right shift the decimal point right now, rather than when/if Bitcoine becomes more mainstream.
If they did that though, even though it wouldn't warrant any market change in the slightest, would probably scare a few people who didn't understand it and destabilize the market even more.
Anyone can have their client display whatever (sub) multiple of Bitcoin he wishes. The reference implementation is free software an anyone is welcome to modify it or make one from scratch. Non-programmers can hire a programmer.
Go ahead, stop crying and modify your client and distribute a patch.
It wouldn't work well unless everyone was using the same standard.