libman,
I just don't see the problem with the GPL license. The BSD license permits people to take free source code and lock it way and not share back, the big example here is Apple, and Microsoft's TCP/IP stack from 90's. The way I see it, GPL is an immunization for the user community against the jerks who want to take source code and not share back their changes.
I understand that some people don't see why it's important to immunize the community against for want of a better analogy I call antisocials. Certainly I understand why corporations like Apple and Microsoft don't want the community to be protected from people who take without giving back, but you haven't given me a good explanation yet for why you believe GPL is restrictive.
Yes, in terms of antisocial exploitation of software I suppose you could say it's restrictive. In terms of being able to make use of the software and modify it at will, I think it's awesomely free. The issue I personally have with the BSD license is not the terms of the license, but that it makes no provision to stop exploitation by corporations like Apple and Microsoft who do not have a history of share and share alike, but instead, a history of aggressively attempting to exterminate any competition.
Personally, I'm looking for a software license that makes the world a better place, not some Darwinian winner-exterminates-all-other-competitors where the only survivors are the companies with lots of $$$ whose priority #1 is to make more $$$ by any means necessary such as suing competitors with BS patents.