That was why I didn't understand why 'Arry felt the need for Keane - before that he was obviously planning to make Defoe the star of the team, and he tends to prefer a little & large combination too.
I don't think you need 4 top-of-their-game strikers: when we got Bent I said I didn't think we needed him because if you have 3 strikers expecting to play in the first team you can keep them all happy and you've got a bit of cover, I think it'd be better (longterm) to have 3 great strikers and an 'understudy' - I expected Pekhart to take that role before Bent came along. It would have been a great opportunity for him to learn from Berb, and the added responsibility for Berb should have calmed his thoughts of being better than the team... in theory.
I think having 4 'proper' strikers means that 1 will rarely get played (how many starts has Campbell had?), and as it's important for a striker to get a run in the team to get the goals that's no good for them or us, whereas if you've got someone breaking through they'll be happy to take a back seat for a couple of seasons while also being more likely to make an impact when they do play because they need to prove themselves to safeguard their future.