I imagine I am using the new cert. My question is that if an attacker got a hold of the past one, could I be MitM'd? They removed it from the Windows CTL but didn't mention anything explicitly about revoking it for everyone else...

Microsoft issues its own certificates, so if they add it to their own OCSP revocation list it will fail an OCSP check from any device. That said, many browsers don't do OCSP checks or will just accept a certificate if the OCSP server cannot be reached, although this was presumably an EV certificate where that attitude is less common. I'm also guessing this made it into Chrome's CRLSet (this kind of high profile EV revocation is exactly what it was designed for), so if you use Chrome you're pretty likely to be okay.

edit: Actually I just checked the Chrome CRLSet, it doesn't appear to have revocations for any certificates from "Microsoft IT SSL SHA2" :(. You can turn on OCSP verification in most browsers, which should do it.

EV certificates can't be issued for wildcard domains, so probably not EV :)

:P forgot they said it was a wildcard (it was only in the title, you know).