I think LGA is a big mistake. Unless they can implement the flexibility of the AA and Delta shuttles (decreased check-in and door closure times, more lenient flight changes, etc.), it will not appeal to business travelers, especially those who have been taking Delta or AA for years (or even US Airways back in the day when "shuttle" meant something). With the Blue Basic devaluations for Mosaic and JetBlue's inferior reliability, I don't see anyone jumping ship from the legacies.
The other cities are certainly interesting, but not unexpected. I am very eager to see the additional flights to SJC, and PHX. Too bad it isn't from JFK.
-J.