Without a doubt: Bioware. Bethesda is great and Morrowind is my favorite game ever but Bioware is able to emotionally engage you in the story and world while Bethesda cna just provide the world to get get sucked into. Square Enix isn't so good, maybe in the 90s but they have been making the same game over and over again. It's not just their signature style anymore, all great developers have their own style but Square is just taking the easy way out. It's up to SE to bring a revolution to the JRPG just like BIoware did for the WRPG genre in the form of KOTOR.