[Blade Raider]

Personally, I'd like to see something completely different. For starters, the series is called SuperHero Taisen. It doesn't and shouldn't limit itself to Rider and Sentai. Let's make Kikaider and Inazuman the stars. Maybe update their origin stories along with the suits.

Secondly, segement the movie like a Kamen Rider Movie War. I'm not a fan of this, but considering Kikaider and Inazuman don't have shows at this time, it's for the better. Gives them each time to shine before they meet. So give Kikaider a segment, Inazuman a segment, and a crossover segment at the end.

Finally, keep it low key. Wizard and Kyoryuger (because Gobusters will be over by then) would act as supporting cast for the 3 segments and join them in the crossover ending, but that would be the limit of the crossover. I have no desire to see that many characters reduced to background cannon fodder ever again (Nor do I ever want to see a fat Black RX again).

And before anyone says it, I am fully aware that this will never, ever, happen. It's a much better idea than anything Toei will make, so of course it won't happen.