I really liked Drysdale in his draft year. Great skater- better than Buium- and a good defender, probably better than Zeev also. VG offensive player, but Buium is better there. Buium playing in college, a higher level than the CHL, also gives him and edge, and while Buium is only an inch or so taller he might end up being more sturdy.
Basically, a lot has gone wrong for Drysdale so far in the NHL, even though he has shown flashes of high end talent. It hasn't helped that ANA (IMO), rushed him to the NHL before he was strong enough to withstand the league. If he fully heals, and is in a positive environment that allows him to rebuild his confidence, he should be a top 4 dman at a minimum for a long time.
He is a RHD, though, and Buium is a LHD. Buium might not be "big", but he is going to be at least 6'- 6'1" tall, and probably end up about 195-200. He also seems to be one of those guys that looks very solid on his skates. I don't think that PHI is one of those teams that is so talent laden on the back end that they couldn't have used him, but Luchanko was definitely a riser in this draft. He has a lot of the qualities that make Jarvis so good for CAR... great skater, very smart, maybe not quite as skilled, but a better two way player.
To sum up, I thought it was a bit weird that Buium fell to PHI and they didn't just take him, BUT, I really liked Luchanko, and was hoping for him or Helenius at #13 for the Wild. Buium seems to have much more star power, and higher ceiling... the guy did freakish things offensively in a better league than Luchanko did in his. I haven't followed York much since he was drafted, but is he really that good that you don't take Buium?