M2's Matsuoka, formerly of Compile, worked on the arcade sequel, Sun, & has talked about how one-upping Tsu was nigh impossible
Hosoyamada joined Sonic Team around then but was working on other games like the overseas version of Billy Hatcher & Sonic Battle
in the year since OG Puyo hit Sega Ages, they've been working on the netcode so it should be better now
they've also added a new very easy AI setting & a 3-color puyo option