If Walcott or Welbeck scored fifteen goals or more from out wide and Sanchez or Giroud scored as many as they have done this season upfront, then it's possible we could definitely challenge for the title.
The problem is both are often injured and both are not prolific enough to do that, and are too inconsistent.
I agree about Cazorla.
Wenger really needs to find a suitable replacement in the next window, unless he can somehow keep him fit, but even then he will need replacing soon.
We have more than enough attacking options, it's the top quality match winners we are are short of, and they don't come cheap.