It's always been the case that he more often than not, needs 3 or 4 chances to scored 1. And (rarel) in good periods he'll score from all of his chances. He definitely doesn't get as many chances fall on his lap as he would playing with the likes of Xavi, Iniest and Messi. It's the main reason I felt David Villa would come here and absolutely destroy everyone and to be fair Ibrahimovic had been fairly clinical up until recently. Hopefully he'll come back from his suspension, fix up and get plenty of chances.
As for Eto'o he'll always be great and i'm sure a period will come where he won't be missing the majority of his chances.