The real question is whether or not Future Hiro actually made any kind of difference – or more to the point, if he even can.  It depends on whether or not the writers are working from the standpoint of the past being alterable or not.  If you recall in the episode about the girl with the eidetic memory, Hiro said he actually tried multiple times to change the past and keep Sylar from killing her but no matter what he did it always came out the same.  This is a very commonly held belief about time travel – the past is the past, and anything that could have happened already has. 

So…One theory is that everything we’re seeing in the show is what already occurred in the future that we saw in the most recent episode.  Hiro based all of his research on the paintings of Issac Mendez and news articles.  He assumed that Sylar had actually killed Claire based on the paintings that he saw, and sent Peter to save her.  Thing is, Sylar already HAS a regenerative ability of some sort.  He has been shot numerous times in the show and was actually pronounced dead by the doctor at Primatech Paper.  It may not be to the extent of Claire’s ability, but he can shake off some serious injuries.  If he can come back from the dead and heal from gunshot wounds, he should be able to heal from being stabbed by a sword from someone who has no idea how to actually use one and wouldn’t know how to effectively deliver a lethal blow. 

In other words, Sylar is going to heal regardless.  Peter was always the one who blew up, and the only people who knew that were Peter and Nathan (and possibly Linderman).  Nathan covered it up, blamed Sylar, and Peter (because he’s all kind of emo) never even told his closest friends.  Thus Hiro was operating from a false assumption all along.

Now…things that make me think this is NOT the case.

The scar.  It would appear as though Future Peter never met Claire.  There is something significant about the scar in any case.  Peter should easily have healed it if he had met Claire, so either he never did or it was an injury so bad that even his powers couldn’t heal him fully (and he’s come back from the dead as well, so that would be a pretty intense wound).  Of course, blowing up could be a pretty intense wound…but that looks like a sword injury – making me wonder if there wasn’t some reason that Hiro and Peter ended up going at it.  It would certainly explain why there is some tension between them.  Future Hiro and Ando made the claim that they had saved her, and got Bennet’s attention by saying she was alive.  But they hadn’t actually CHANGED anything.  Claire was always alive in the “dark future.”  Bennet had made the claim that Sylar killed her at the prom to protect her, and panicked when they acted with the knowledge that she was alive.

Another Edit (based on something

zayna

said) – The Haitian could indeed have been nullifying Peter’s powers, but he would have to have been doing it on purpose.  He actually has to focus his powers and intentionally be blocking someone (recall he was standing near Eden when she used her powers on Sylar).  He’s working with Peter’s mother, and there hasn’t been any reason to assume she’d want to harm her son.  He’s actually her favorite of the two, and she’s been very “den Mother” over both of them. 

Claire knows who her Father is, though, and had obviously met him in the past.  How she would have met Nathan and not Peter is a mystery, but not impossible to conceive considering the fact that the Haitian works with Nathan and Peter’s Mother (who is possibly “special” herself and at least somewhat aware of what her husband was doing with Linderman). 

Future Hiro doesn’t seem to have any recollection of visiting the future with Ando.  When they first met he even said “You’re not supposed to be here,” so unless something happened that caused him to forget (the Haitian),  he had never traveled forward in time.  This would lend itself more to the “Back to the Future” kind of time travel, where certain key events in time spring off to different end results.  It would also mean that Hiro can not only travel through time, he can travel to different time lines – regardless of what ends up happening, what he visited is clearly NOT his future (unless, again, the Haitian erased his memories of the event).

Future Peter also didn’t seem to recall the event in the Subway either, but that wasn’t entirely clear so hard to go with.

Other observations….

Micha died in the explosion in New York (Peter to Nikki – “I killed Micah”).  DL was obviously killed by Sylar at some point, because Sylar has his powers in the future.  This means Micah was in New York at the time of the explosion.  This might be explained when we find out what Linderman has in store for him.  I’m assuming he’s using Micah to affect the voter records for touch screen voting machines in New York to get a win for Nathan. 

Edit – This would also mean it was likely Linderman died in the explosion, but he knows it’s going to happen so why?  It doesn’t seem likely he’d let someone as valuable as Micah die.

Sylar painted a picture of himself as President in the future, in the same pose as Nathan in the picture that Issak painted.  From what we saw this week, we now know that Sylar killed Nathan and took his place at some point.  The question is whether or not Issak paints pictures of a POSSIBLE future, or if his ability is infallible.  As far as I can recall, everything he’s painted so far has come true.

I think the delivery person who took Issak’sfinal print was Future Hiro.  It would explain how he got the copy of the unpublished comic, and sketches he was using in his time line (from the Sketch book Issak gave him). 

Edit the third – I’m a big fucking geek.