Love the Captcha update - for some reason my Windows 7 laptop only spits out "FFFF" in the verification field, but it works nicely on my Windows Server 2008 R2 desktop. Haven't rebooted (which shouldn't be necessary), so it's probably just a minor glitch
somewhere...
The diag tools are great, but you still haven't "fixed" the Exchange ActiveSync diagnostic. It connects with EAS level 12.0 (Exchange 2007 RTM) which doesn't fully exercise all features of Exchange 2010 SP1. It also means if you don't allow non-provisionable
devices you'll get an HTTP 403 without any instructional clues as to why you're seeing this error. (Since you do an HTTP OPTIONS before attempting the FolderSync you could adapt the request accordingly.)
I'll easily admit that the UI is far less intuitive than yours, and it focuses purely on ActiveSync, but I've put together my own online diagnostic at
easmd.labs.mobilitydojo.net ,(remove link if you consider this spammy), where you can get around these issues.