Perhaps a Sakura Wars game? There's very few released in English though. And not sure if many of the others are worth the trouble to get into English, as the first three (I think?) were Saturn games. Which is notoriously hard to emulate, and once emulated, pretty hard to even run on even the newest computers. You may enjoy a YouTube Lets Play though

I actually had a couple of games in mind, but they wouldn't match much of the criteria. I feel compelled to suggest Shining Force games though, despite how outdated and ancient they are. They're really cute and fairly easy yet super enjoyable strategy role playing games for the Sega Genesis. And just like you like them, they are super bright and colorful (especially SF2) despite the dark and evil things happening in the world