Sure they are. Give me a situation where it’s a problem.
Haunt is fine. This would be like me complaining that you can heal.
As far as master channeler, just run out of range and the drain life stops. Just cc the lock and run. Easy. Or better yet just bubble immediately after it’s cast. Then the warlock has to wait all the way for a long cool down to use it again. You should have him dead by then.