Finally 'finished' Double, and it's looooong. Double was least twice as long (no puns) as the other riders done so far, and that's WITHOUT the memory gadgets, Philip's own stats, and CycloneJoker Xtreme. BUT, I'm very satisfied with the results so far, and it looks like one of the most fun rider to play out of the ones I've made here... that is if anyone would actually play a Toku game on tabletop. *sigh*
Sentais gets trickier, since they have a lot of team and theme-based abilities where the game system is mostly focused on the individual. For example, their combined weapons system will likely require a Flaw of all members being present. The trickiest thing to get done in M&M will probably be the mechas, which I don't think I'd want to get into the details of as it can be very subjective to how it can be done.
I've really no clue. I guess you could try looking at BESM, but I've never played myself so I can't say how well that will work.
Then what game system would you recommend if I wish to run a Super Sentai tabletop? Some system that can encompass everything about Super Sentai, including the mechas.