Personally, I don't recall EVER thinking he would be a saviour. He certainly hasn't met expectations yet, but there is plenty of time for that to happen. He would've been a better complementary player if Bergevin had been able to keep Radulov and had, somehow, managed to add a top-6 C to the mix.
With Radulov controlling the puck along the boards and being able to make plays, even if the Habs had been stubborn enough to go ahead with the C experiment for Drouin, it would have had a huge chance of working out better.
However, I don't think that the Habs would have kept Drouin and Radulov together long enough if things hadn't worked out. The pressure to reunite Radulov to Danault and Pacioretty would've been too great.