Adam's basically had super healing. All aging is "breakdown" from DNA level up. Adam didn't heal b/c once his power was activated, his body repaired ther damage that occured dailt...hence he didn't age. So, once that power was removed, he would have normal healing ability and would begin to age from that point on.

 

The best season was season one but then the writers found a stupid-idea-generator and screwed it up. This was supposed to get "fixed" this season with the creation of an arch. I suspended disbelief for the first few eps hoping they are really getting back on track. I dunno. I'm still watching but like some of the other comments I think it's ridiculous that:

- Time travel poorly used and crazy paradoxes have been created.
- Stupid ladies and puppeteer, just ridiculous
- Maya speaking perfect english. WTF?
- Hero can all of a sudden put Adam back in coffin. That's not time travel or him moving in space. This is new.
- BUT Hero can't use his powers in level 5. Is the Haitian ALWAYS there? You don't see him. Other people have their powers down there.
- Why didn't Peter get Mr. Petrelli's powers?

Oh and, yes you make sense Steve but that wouldn't be as cool as turning him to dust. It's an old chestnut to do that... so of course this show couldn't resist using an old chestnut even though it isn't logical.