I'm seriously hoping they pull a Mikoto Nakadai/AbareKiller with Rio & Mele's characters. If it's done like that it'll be simply awesome.
If the writers can hold off making them good until the mid 40's of the series I'll be as happy as a pig in ****.
Now, if they do end up turning good much earlier the other option I would like to see them doing is pulling a Gouraijer style. Have both characters off on their on and not too involved with the main team at first, same darker attitudes, emo stuff, having their own agenda, not accepting the Gekiranger team right away, yadda yadda yadda. I see this working for them.
It's either the Gouraijer way (minus the getting weaker part) or the AbareKiller way, imo. Unless the writers have something totally different in store for us fans.
One thing that will destroy everything for me is if i see Rio & Mele turn good and a few episodes later being thrown into lame ass comedy relief scenes or that gay ass "EHHHHHHHH?" thing the Heroes do, it annoys the living **** out of me.
Rio & Mele together have the potential to be the best villians in Sentai since the '80s. The ball is in the writers' court... hopefully they won't **** it up.