Beasley is an enormous talent who came out early, hence the immaturity - which I'd hasten to remind all of you isn't a permanent condition. See Rondo, Rajon for further proof.
Further, he's not exactly surrounded by mentors in Miami. If I'm not mistaken, he's 20 or 21. I know people in the business who insist he's a great kid who desperately needs peers to teach him how to be a pro.
Make no mistake about it: If I could get Beasley for Perkins, I'd do the deal in a second. Move Garnett to the 5, sign a banger to back him up and entrust Beasley to Allen, Pierce and KG. He'll grow up quickly, and we'll get the young "bridge to the future" scorer that this franchise desperately needs to pair with Rondo.