Good thread Corey94, I love a chance to discuss a player's stats, though I disagree with your interpretation of them.
Just to back up Capital Shark's good analysis of those figures, 43 missed tackles compared to 138 made gives Kimmorley a missed tackle percentage of ((43/(138+43)x100)=24%. Just to compare, his rate last year was a little better at 17%, but I agree with Capital Shark that his kick chase this year has been fierce which will add a little to the missed tackles. Also, even though he was injured a bit last year he has already attempted about half as many tackles as he did last year, only 6 games in.
Last year, 17% was about normal for halfbacks, and his current 24% would have been on the bad side for halves last year, similar to the other halback liabilities in the game such as Orford (22%), Thurston (23%) and Prince (24%). I would love to see how making an attempt on fullbacks affects your missed tackle %, but I'm not sure I can find stats for that- but the conclusions of the others in that regard are certainly born out by fullbacks and then wingers dominating last years stats of line breaks and tackle busts made per run.