Unless you chose the school and tried to jump into PvP you probably wouldn't even notice, and even then I really doubt it. These spells are still very powerful in PvE and reap great value. I wouldn't say it's worse in PvP because most people aren't wandering around fully buffed at all times under a wizard's thumb. Our hypothetical wizard solo ganking another fully buffed wizard and his party should be happy he still has a few tricks up his sleeve that do not allow a save.
It doesn't really matter if you're a caster or not, "optimal" PvP will always revolve around catching people off guard because the game enables and incentivises players who want to win to do just that. Wizards don't really lack "I win" buttons to instantly disable or kill people, and most people are definitely not wandering around with mind immunity active. If someone pulls a dreamcatcher on your wizard, illusionist/enchanter or not, you still have so many other options.
e: I just want to be clear, the only reason I'm posting this is because it's relevant to the topic at hand: consumables don't make casters weak or upset the balance. Anyone who goes all in on one tactic should be ready to lose if they're engaging with people willing to counter them, especially considering there are tactics they can use to avoid being countered. So a mundane can get a minute or two of mind immunity by using a dreamcatcher when he sees a wizard trying to gank him. That gives him a few rounds to have a fighting chance at best. We can talk about all the counters mundanes can do to fight and kill wizards even in a counter-gank situation all day long but it's still a pretty tired discussion, and counter-engagement is good gameplay anyway. It's also rare because of the game design. (The fact he even saw the wizard first doesn't guarantee he'll think quickly enough to block whichever spell the wizard tries first, and again, not all can be blocked. If an item means a wizard has to press more than 1 button to win what might be pivotal PvP with months of consequences behind it, the balance is not upset.)