In all honesty, I don't care what theme they use. I just want to like how they pull it off.
What I would hope for next year, is a better balance of story and development, for both the heroes and the villains.
Now, I know that is completely not the point of the topic... So. Hmm...
It would be nice to not deal with time travel in any way shape or form.
It would also be nice to not have a vehicle motif. Though, I've never really thought of what type of theme I could possibly want. Maybe some sort of mechanical, technology type... but not like Megaranger? I really, really don't know.
And since I don't know what themed sentai I want, I can't really even try to come up with mecha. Though, I really did like the movement of the GekiTouja, so... Anything that makes me actually look forward to the mecha battles.