Don't know what are CC\damage immunity you talking about.
Let's take fire damage and some, hm, drake.
Give the drake 100+ DR to fire - omg, immunity is here!
But what about CC? Oh. Let's give this drake some unbeliveable reflexes(or what that CC attacking) - voila, immunity to CC is here!
There is no need to develop the wheel. Some rebalance in spells\abilities\stats - and we've got all that immunities.
sorry for my bad english.