originally i saw this on a parody of heroes, but now I can't help thinking myself..
why doesnt hiro use his powers for something like, stop the kennedy assisination, stop hiroshima and nagasaki atom bombs, stop 9/11 etc etc??

instead of all this takezo kensei nonsense!!

Your right, some things are left to fate.

He would drastically be altering time by stopping those events. Not to mention, you'd have to ask why not save everybody that died outside of natural causes throughout all of history. He'd be spending eternity doing that and changing the future, possibly resulting in preventing his own birth.

I saw the MADtv parody you're talking about and while it was amusing, it definitly didn't understand (nor did it intend to ) the complexities of time travel.

Carp! Don't forget he also learned a painful lesson about changing the past through Charlie.

yes, infact if you think about it HIRO NAKAMURA IS TO BLAME FOR EVERYTHING -
if he never went in the past and betrayed Adam, he wouldnt hav turned spiteful and vengeful and felt the need to start the company etc etc
but then again, he is evil-natured by default so he might have done those things anyway

Adam didn't start the Company and plan on destroying over 90% of the Human population because of what Hiro did with Yaeko. It might have turned him bitter towards Hiro, enough to not care about Hiro's quest of stopping Whitebeard through Takezo Kensei(sp?). Living through 400 years of wars, plagues, famine, poverty, genocide, racism, and death is what turned Adam the way he is. He grew a god-complex and believed that like God (of the Bible) wiping out most of Humanity, he too has that responsability. Adam was clearly loco and not because of Hiro and his lack of control of his powers.

hiro was a fool and should have had the common sense to know (from earlier events in the series) that messing with the space time contium to do anything other than help adam become a 'hero', is a dangerous feat which could totally mess up the future and should be avoid at all costs. he even said once i think 'even stepping on a single bug could destroy an entire species or make it extinct' its not like he was drunk with yaeko and lost his self control, he was fully aware of wat he is doing

it is UNFORGIVABLE

his love of the generations of people to come and destruction his action might bring should have taken precedence over his love for yaeko