Peter should have absorbed the Haitian's ability by now, and yet he still can't use his powers around him.
I would think that the Haitian would have to *allow* Peter to absorb his powers. H's ability seems to be the only one Peter could never really absorb: every time he got anywhere near him in order to do so, his sponge-power would be negated. I don't think Peter will ever get H's powers.
Which is a good thing, IMO. Peter should really have more limitations.
GG
I think that Peter could absorb the Haitian's power if the Haitian was unconscious. Earlier this season Ando knocked him out, and while he was out Daphne was able to use her ability. But I do agree that Peter needs limitations. No one character should be allowed too become to powerful.
Which is why it's good that Peter lost his powers. Now that he has his initial power back, he's back to square one. With at least some limits to what he can do. Though it does kind of suck that he lost Claude's power. But then again he also lost Ted's power.
In my opinion the first thing that he should do is go find Claire. Her power's one that he really needs.....

Pete should find Sylar, then he can get a whole load of powers at once (healing, telekinesis, freezing, electricity, ect.)
But maybe that would be too easy.