To me, Rondo solidified himself as a top PG in the 2009 playoffs when KG was out and Ray Allen was playing largely inconsistently. Rondo goes on to unquestionably being the best player on the team, and nearly averages a triple-double for the entire playoffs.
I don't see why he's getting knocked so hard for his inability to shoot though. He shoots over 50% from the field, so even if he's a poor shooter, he knows his limitations enough so that it's not a detriment to the team. It's similar to what some have brought up about Tony Parker early in his career. He wasn't a great outside shooter, but no one could stay in front of him and he was such a great finisher at the rim. Rondo scores efficiently and he's steadily improving his outside jumper. Of course, he needs to get better and continue to improve his stroke. But it shouldn't preclude him from being a top 5 PG, especially considering it doesn't affect his FG%. It's just like Jason Kidd for much of his career not being a very good shooter, but he was still widely considered a top 5, even top 3 PG, even when he couldn't shoot at all.