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.
How do you plan to do that?. Bitcoin is decentralized. It's naive to assume you can get clients to follow a same standard regarding the user interface. Even regarding the protocol, there will be broken implementations. You can't but invite people to use the denomination of your preference.
The only reason people are getting involved is because they know that there is a limit. Who in their right mind would invest in something that will be diluted infinitely? The price of bitcoins would still be at $0.001 if there was an infinite supply. An infinite supply mean that no matter the demand, the price is going to be tiny, because there will always be more.
The first is just your opinion (Which is fine), the later is misleading and untrue, because demand could rise with supply, bear human population growing rate in mind.