In fact, if I am not mistaken, Ryuki was originally supposed to be a "real" Metal Hero show.
Pretty much, it seems like 90% of the original idea for that Metal Hero revival made it into Ryuki itself.
I'd love to see Metal Heroes return, they always did have a rather unique aesthetic that I honestly don't think the current Kamen Riders imitate...well maybe the whole G line in Agito, DiEnd, and G Den-O, but otherwise, I think the Kamen Rider designs since Kuuga are more Kamen Rider than people think and not thinly veiled imitations of a dead franchise. It just always seemed to me that, for the most part, the Metal Hero aesthetic was defined by the fact that every piece of the suit was intended to look metal, not the case in the current Kamen Rider line. In fact, I'd say the shows from Kuuga to Kiva were closer linked to the original design of the first Kamen Rider in the sense that it's basically chest armor, spiffy boots and a spandex or leather under armor. (though Heisei Riders also have the knee guards)
As for the franchise dying with dignity...have any of you actually
seen either Robotack or Kabutack? Or are you just going on the designs? It's a lighter incarnation of the franchise, obviously, but the shows were very heartfelt and were the type of feel good shows that I think there should be more of in this day and age. The shows had fun characters, interesting fights, colorful plots, and rather unique ideas. I'd love for either one of them to subbed (though I'm partial towards Robotack) so more people can see just how awesome they are.
If Metal Heroes could return, I'd like for it to be something different than what we've seen, no Space Sheriff stuff off the bat or a third entry into the B-Fighter line, but a nice, strong stand alone series that can really show the strengths of the franchise.
...buuuut after how badly Metal Hero Spirits bombed, I doubt we'll get one, though it would be neat, Toei does want to make money forever.