Papa Shango
Player Valuation: £70m
Of course they can improve, especially when as young as he is.
You can argue the toss either way over Martinez as far as I am concerned. I for one was very impressed with him after his first season and didn't actually start calling for his head until the 3rd season when it was clear he was just spouting crap and we were going backwards and at that point looked a very bad manager.
As of yet though, he still has to prove he is a good manager. Stevie Wonder could manage this Belgium side to the latter stages of a tournament.
What I will debate though and put a counter response to is all this, "72 point best ever PL season" garbage. Our best season was 4th under Moyes, who also gained 3 x 5th place finishes which Martinez managed to equal once.
Its not a fair debate that though. In his first 3 (full) seasons he came 7th, 17th and 4th. The 3 x 5th placed finishes are nice (ish) but that was over 11 seasons. Martinez only got 3 (and rightfully so, it was time for him to go) but could he have done it over 11 seasons? Possibly.