League of Legends (LoL) Question: Malphite in S4

Depends what you mean by viable. He's always been a viable jungler but his awful pre-6 pressure and mediocre clear speed have prevented him from being a strong pick. He still has godlike ganks and initiation if you can make it past the early game without your team getting wrecked.

This season his early clear should be okay because of the low smite cooldown but the jungle monsters will scale harder and you'll have trouble clearing camps later on in the game. You might want a Sunfire Aegis to help with that or something.

imo it is too slow and he needs quite a bit of money to get really beefy

I'd say pick someone like Vi or Shyvana if you want someone who is able to do the same job, but better.

Malphite is too slow of a jungler and his ganking potential pre-6 is quite low. So no, he is not viable,