If we take it that he has 18 assists so far, that's 28 goals/assists in 21 starts. I'd say that's pretty good.
The main reason he only has 10 goals while Suarez has 19 is obviously because they're playing completely different roles. Rooney's had 47 shots in 14 games. Suarez has had 77 in 12. When Rooney was given the freedom to play Suarez's role and concentrate solely on his end product, he went on a run of 18 goals in 13 games in early 2010. This of course included the winning goal in the CC final, the 90th minute winner against City in the CC semi, 4 goals against Milan, the opening goal against Bayern and goals against Liverpool and Arsenal.
What has been so impressive about Rooney is his ability to produce in a variety of roles in an underperforming side playing with no fluency whatsoever. Given what he's produced in these conditions, there's every reason to believe he would be performing at unbelievable levels if given the right platform to play off. He was obviously sacrificing his own game and personal productivity goals for the team yesterday, for example. Suarez has not had to do this once. Bale last year did not have to do this once.