I’d do X-Files with Mulder and Scully training new agents to deal with new threats alien and supernatural, and I’d conclude it after a few seasons with the aliens invading and having to deal with not only the expanded X-Files program but the supernatural creatures too who would not be happy to have them there.
X-Files is definitely a show that shows its age, in that it desperately needed to have actual arc progress, and yet wasn't really allowed to have arc progress.
Anyway. . . Heroes. I would do a "reboot" of sorts, which is to say, it would look like its a reboot all the way back to the beginning of season 1, trying to tell the same story again only with better writing and budget. This would *maybe* last to the end of the first episode, when things would very very obviously go off rails. The trick is that. . . basically, the story of this reboot is "Future Hiro from further down the timeline said 'screw it', and came back and changed *everything*." Think something on the order of "The Company was taken over by Future Hiro Nakamura years ago, and its top superhuman agent of Gabriel Gray, who was recruited and trained by Hiro and thus never went evil".
Its basically an excuse to play with some of the "toys" that Heroes established ( and then either wasted or set on fire ) without being beholden to the largely terrible *plotline*, along with some higher end concepts like alternate timelines. It also would be a way to segue into the show eventually being about a *non-stupid* public superhuman setting. The big public reveal of superhumanity would definitely be some kind of Superman style "A disaster happens that would mean certain doom for countless people, and then out of nowhere comes a living miracle to save the day" event.
( Also, Young Hiro's own subplot would *definitely* involve "Investigating suspicions about how ruthless and manipulative Future Hiro might be". Since even if the answer ultimately turns out to be "Future Hiro actually is the idealistic champion of the world", it would make perfect sense for some people to be worried about such. )
