Time travel/messing with history is a staple of fiction/science fiction, now. I haven't read One More Day, and I thought of the Mephisto idea (for Alpha Flight) long before OMD came out. Dept. H would not depend on children to defend the country against the types of threats the original Alphans faced: volume 2's version pretty much confirmed this when Mesmero hypnotized the whole team, newbies & "veterans."
When I was growing up, Marvel used to be known as "the House of Ideas." A lot of the things Marvel did hadn't been done before. Maybe it's time Marvel became that innovative house of ideas, again.