I have no problems with Victorious per say, it's a decent show that has some good lines and some decent acting. The thing is, I can't see myself ever watching any of the episodes more then once, I feel they will immediately get stale. I can watch each episode of iCarly more then once and be fine with it, but with Victorious I just can't, maybe it's because there is a lack of depth, I don't really know.
Nickelodeon will survive after iCarly ends, it will be fine, it just won't have as many quality shows. I'm sure they'll give some iCarly character there own show in a few years and that might be good. Who knows? I just say we'll see.