If you listen to podcasts from some of their sites, its not very pleasant as to 4E and the GSL...
I listened to some casts from Green Ronin interviewing themselves and Paizo, as well as a few podcasts linked on their sites, and I got the impression there were stronger plans to throw weight into True20, Pathfinder, and even Savage Worlds.
There's fear that the GSL might someday be revoked as has just happened to d20. Beyond any system preferences, that's a major issue that a publisher needs to take into account. There's also concern over the way the GSL has been discussed to date, and the limits it has had and not had at varying changing points. I think there was also some cconcern that the GSL might be more restrictive on genre/content allowed than d20 was - requiring perhaps a particular style of fantasy... or not.
They're working off of rumors, and those introduce unpredictability, and unpredictability is a very bad thing around which to make a business plan.
EDIT: Looks like Pramas has posted here. So, be aware my post is the impression -I- got from those podcasts.