It's very early, but yes, I think Matthews looks not only like he was worthy of a late #1 pick, but worth Thompson trading up for. We deperately needed a full-time OLB for our new 3-4 defense (good against both run and pass). If we hadn't traded up and kept our 2nd round pick (#41), here's who we could have had instead: Everette Brown (went at #43 to Carolina), Clint Sintim (#45 - Giants) or Connor Barwin (#46 - Houston).
Brown was an excellent pass rusher in college, but bad against the run (another KGB) and scouts questioned his ability to be a 3-4 LB (play in space/defend the pass). What McGinn's NFL scouts said: "This kid doesn't play the run at all. Just weak and non-competitive..." Brown a back-up to Peppers as a 4-3 DE.
Sintim read just OK. Good against run and pass, played in a 3-4, but instincts and overall production questioned. My friend who's a Giants fan says Sintim has hardly seen the field this year, and is a back-up LB in a 4-3 to Danny Clark (who?).
Barwin, like Brown, was a projection to 3-4 LB, and many thought he was drafted too high on his athletic potential. He's now a back-up 4-3 DE in Houston.
FYI, there were only two LBs taken in round 3: DeAndre Levy (Detroit, 4-3 back-up LB) and Tyrone McKenzie (ILB in New England's 3-4, put on IR in pre-season). Neither read one bit like a 3-4 rush LB.
Bottom line, we got the only true 3-4 run/pass OLB available at the time, and so far he's proving to be a quality starter with huge upside. I think this is looking more and more like one of Thompson's very best moves.