Where is the proof that a majority of players are bad and can't do scripted fights? Of course there are people who don't understand mechanics of a fight, but to say having more randomization in a fight is a bad idea because a majority of players are too "bad" is a horrible reason because you're not basing that statement on anything measurable.

Bottom line is, if encounters were a little more randomized, I know I would have fun. I want that feeling you get when you fight a new boss for the first time, it's scripted, but you don't know whats coming next. I want that all the time.

Server lag however... is a legitimate reason. Fix that, and more random elements can be added to scripted fights.