My concern, as readers who have seen some of my other HN comments may guess, is that the next time someone starts over, they'll neglect accessibility (in the sense of working with screen readers and the like), and people with disabilities will be barred from accessing some important things. "How hard can it be?", the brave new platform developer might think. "I just have to render some widgets on the screen. No bloat!" It's hard enough to make consistent progress in this area; it would help if there were less churn.

Edit: I guess what I (very selfishly) wish for is steady state on UI design and implementation so accessibility can be perfected. I know that's not fair to everyone else though. Other things need improving too.