I love how dynamic pvp is, but I agree sleep duration is a currently too long of an effect. If the first one is 45 seconds, the diminishing returns should be much more stricter, and multiple sleeps shouldn't be chainable.

Basically if someone awakens from sleep and is immediately put to sleep, once they awake, they should be immune to sleep for a long period of time.

Also if your put to sleep for longer then 30 seconds from a single spell, the next duration should be no more then 15...