Actually, 6 months after he got into the scene he came with me to 0C3 where he didn't take pools seriously enough AKA beat someone with sheik and then switched to marth and lost a match which barely put him out of brackets. He wasn't nearly as good then. I got 25th and faced bombsoldier that tourney. Best I've ever done at a huge national. Granted I've only been to 0C2, 0C3, and Genesis.
Right now, I would say dieslow is good enough to get top 10 at a tournament the same scale as pound 4. Just depends how his bracket goes I would think. He's very consistent, and very precise. Plays patiently, and is technical enough to back it up. Diakanos and Blunted Object are also both capable of the same thing.