I too would like WinMo 6.5 on EVO for a few reasons:
1. Zune. Zune. Zune. I can sync up play lists DRM music etc with it via WMP11 to WinMo. It may not be pretty and beautiful, but it works. The Zune service on PC is much better than iTunes. Don't argue with me if you haven't used it, you just don't know.
2. 1GHz snapdragon. Touch Pro 2 only has 528 MHz processor and drags a little on WinMo 6.5.
3. Not huge on separated non-integrated applications. Zune, GPSnav (recently added bing turn-by-turn), web, phone, email, text and maybe tether/wifi router. I don't want to pay for software I don't really need.
4. Not so important, but worth mentioning...business focused integration. Ability to operate closely w/ cloud or on it's own.
Ideally, I'd have a QWERTY slider with the 1GHz or better, WinMo 6.5.x (skeptical about WP7, but looking forward to it), real GPS (not via cell tower), WiFi/AP capable w/ WPA(2). I can write little apps that I might need...because WinMo is open, not controlled like apple or android market.