We haven't seen a lot of it in his last five fights it must be granted. The problem is, he can't help sit a carelessly swinging fool down on his ass. When you have such a powerful and effective weapon, you use it and rightly so but that is another debate.
Although we didn't see much of it, that is not to say his stand up striking was nonexitent. We saw him drop both Fitch and Alves and seriously connect on Hardy and Penn all the while taking absolute zero damage. His footwork is almost as good as the legendary(!) Frankie Edgar. He has strong legs constantly on the move, never still. He extends his jab really far and quickly too. His superman jab appears to be a big asset in his arsenal along with the more traditional superman punch, the big right hand, the spinning kicks and punches. His one-two punch combination followed by the leg kick has been used in all of his last 5 fights. As we saw with Penn, Fitch and Hardy, GSP often goes for body shots with accuracy. You name it, he throws it. He had no problem with anybody's clinch (except maybe with Alves where he preferred to push back more). As for his chin, since that Serra punch (I'll let somebody else mention where exactly it landed) he has shrugged off everything that has been thrown at him. His chin is rock solid and reliable.
It's fair to say St-Pierre is running a tight ship in his training. Every variable of the equation is analyzed and every systemic anomaly (this one's for you Matrix fans) is solved.
Albeit complete and polished, GSP's stand up striking is not perfect. For one, his head movement needs more work. He takes too many inoffensive yet unnecessary shots to the head. Secondly, his power does not kill. He smashed Fitch, Alves and Penn and had them hanging by a thread yet they all survived (at least survived long enough to quit). Did he lose some striking power when he turned monster wrestler? Maybe. Does GSP still have the killer instinct? Maybe not, as we saw with Hardy. If he manages to slip more punches and knock out someone dead cold soon, we'll be ready to talk about near stand up perfection.
Finally, the best scenario would be a Shields fight. That would be a dream fight for me as we would see St-Pierre do to Shields what Henderson did except GSP would not get tired and he certainly wouldn't get taken down unwillingly. Let's all pray for Shields to make the move to the UFC because no matter who wins, Koscheck or Daley, the motherf'er will get taken down. And that will be that.