I’ve got one main concern about IE7: considering the way MS has been thinking, what’s the odds that it’ll include deliberately-engineered incompatibility with (or even disabling of) popular 3rd-party anti-malware goodies like avast and others?
We saw a lot of that with SP2, especially in its early beta days. But most of that was sloppiness on MS’s part, rather than deliberate, and at least some of it has since been corrected by them, under pressure from the 3rd party developers and from users.