The only reasons I kept JW Player thus far are (1) laziness (2) it's hard to say goodbye to the spectrum analyzer I implemented into it (for Foxy!)... Heck, it's the one and only time I ever dabbled into ActiveScript.
One of the reasons why I'm trying to stick to Chrome these days (which is made possible by the very nice Sidewise extension -- it's so sad that Chrome doesn't allow it to be part of the window...!), is that it supports the Web Audio API which is the only alternative to Flash for a spectrum analyzer. Thus, using Chrome would make me feel like I'm still with a universal S.A.... It's silly, I know! (Especially since AFAIK, Chrome requires a flag to be set for Web Audio to be supported...)
The plan was always to switch JW Player to use MediaElements.js, though! It still uses Flash, but only as a fallback, like the latest versions of JW Player.
As for mass uploading, I think that at this point, it's not safe yet to switch to a HTML5-only solution. Opera, Chrome and Firefox all support it indeed, but IE is way too late for the party. And this is a situation where I'm not sure I want to provide a Flash fallback... It's pretty much all or nothing.
Anyway -- Aeva stuff is what I'm playing with these days, due to my recent bug fixing. But I keep reverting my changes because, well, I don't know where to go exactly... Flash being one of the 'I'm scared!' ones. But it'll come soon.
It's interesting that this topic was created today because I started doing spectrum analyzer tests last night... :P (And it resulted in a nice little crash.)