I see Palladino as DP's long term replacemnt, as long as he continues to develop.
If we are to play 3 strikers then the 5th strike would get more playing time and so Bianchi would be a good option, however I think CB's are far more of a priority.
Bianchi is a better player but a 5th striker has to be willing to play very little and not complain, which is why Zala is our best option for that position.
The main thing is to have a good finisher. If Arsenal had Trez or Van Nistelrooy playing for them they would have been close to winning the league this year.