Zane
Spirit of the Wolf
Back to NM and Sieg, I have to say Sieg's character is just lame in SC4. He looks like a pale German sissy boy. I'm also not crazy about how they did Nightmare to be honest. I guess I'm critical though as a lot of characters I don't appreciate their appearance. I like the old school Astaroth a lot, Yoshi is well done. I can't actually think of many others.
As for actually playing them. I don't have a ton of trouble with either to be honest. I haven't yet played a Sieg I felt honestly beat me. I very usually beat Sieg, and when I do lose there's usually a lot of whoring of unsafe transitions. Nightmare I mostly feel the same way, but dang Partisan's Nightmare kicked the crap out of me. I guess I would like to see a Sieg played up to that level, until I do it's hard for me to judge.
Until you can make better characters, you can't say they suck or that they look bad. Same thing for those Justin Bieber haters, until you can sing better than him lmao you can't say he sucks =/ otherwise if you say you hate him you just jealous =p