I pretty much agree with Sinfire Titan's analysis, but I want to add that the Wu Jen is a solid, maybe high T2 while Shugenja is probably a low one.
Wu Jen suffers for having a lot of spells that require a regular ranged attack rather than ranged touch, but they also have some nice unique spells and most of the solid workhorses of the core Sor/Wiz list. The Spell Secrets are also a nice bonus. Probably the biggest thing keeping them out of T1 territory is the lack of support outside CA.
Shugenja, on the other hand, only even have access to 3/4 of their spell list (since they lose their opposition school) and half their repertoire comes from their favored school (which comprises 1/4 of their spell list). Without something that adds directly to spells known or some heavy PrCing, they're really good at one or two things, passable at between two and five other things, and useless at a couple more things. That sounds basically like a T3-- the level 9 spells they do get are probably all that bumps them into T2 territory.
I also want to mention that Wild Surge, though awesome at level 1, really drags the Wilder down at higher levels-- not down out of mid-T2, but still down. By 20, he's almost always better off not doing it.
X-Codes is probably right about the Lurk. I wish it were better, but it just isn't.