Speaking of Source Gaming, I couldn't help but notice in one of their recent articles, they listed the most lucrative franchises for each currently represented company sans Square Enix, and Sega's 2nd biggest franchise is in fact....Puyo Puyo. Yeah, y'know, this game.
Oddly, I almost never see this franchise come up when it comes to another Sega rep, or heck, even in terms of Sega's major crossovers. (It only has slight cameo appearances in the racing games, I'm not sure if it even showed up in that one sonic comic event.) Of course, a lot of that can come down to the fact that 1. It was initially developed and published by Compile before being bought out by Sega later on, so most people tend to forget it even is a Sega property! and 2. Sega has been doing its absolute damndest to try and snuff out the existence of Puyopuyo in the west.
Which is a crying shame because Puyo Puyo is a series with a pretty major pedigree, having pretty much invented and codified the "competitive puzzle game" genre, which later went on to inspire Nintendo's own Panel de Pon/Puzzle League series, along with countless others. Both Nintendo AND Sega even infamously reskinned the games to involve Kirby and Dr. Robotnik respectively. It's also had crossovers with Gundam and, recently, Tetris, so it's certainly gotten around here and there.
When it comes to characters, the obvious choice is Arle Nadja, the main protagonist of the first few games (and despite taking a back seat to others in later games, she's still a roster mainstay). You could do a LOT in terms of moveset potential utilizing the Puyos, from being an Olimar/Rosaluma type character, or unleashing effects by bunching up 4 of the same color puyos in a row.
In terms of visual design, I'd probably go with the earlier games since the newer artstyle would be really...difficult to translate into 3D, though looking up images for this post, I found a figure of her recent design that doesn't look too bad.