no. roll planet hulk into guardians of the galaxy. make world war hulk the next major plot point for the avengers.
u cant skip planet hulk. it's too important to explaining why he went world war hulk on everyone.
That's why I said told through flashbacks. It's already been implied that he's going to be shot into space at the end of one of the Avenger movies. they can bring him back for the next one, showing that time has passed and he's stronger and angrier. The problem with Planet Hulk is that it's essentially Spartacus/Gladiator and John Carter. The slightest eff up and it can go from the former to the latter...which no one wants to see. They could however sprinkle some of Planet Hulk in the next Guardians flick and the Inhumans, just a hint of what the Hulk is up to and then have a full-fledged WWH movie. That's how I would do it.