That approach is no better than those who focus only on the number of touchdowns. It disregards the whole picture, which supports his status as one of the best, IMO. Yes, he's 21st in total rushing yards, but he's also 23rd in att/game at 14 (Williams has 10.7, which shows a pretty decent split of carries). Despite that, he's tied for 2nd in touchdowns, 6th for first downs, and has zero fumbles (knock on wood).
Sorry, but I just don't see what people have to complain about other than the fact that he could maybe get more carries and be involved in the passing game more, which he excelled at last year. That's a playcalling issue though, not a Ronnie Brown issue.