Bandai Namco allowed Arc System Works to take a crack at the Dragon Ball property. However, the developers behind the hugely popular Guilty Gear series opted to make the newest Dragon Ball FighterZ on a 2D plane instead of in 3D like the CyberConnect 2 or Dimp titles. Well, there's a detailed reason why, but the short answer is eSports.
Game Informer managed to nab an interview with Bandai Namco producer Tomoko Hiroki, who explained that the switch from 3D to a 2D plane was due to accessibility and eSports...
For those of you who don't know, Arc System Works developed a new shader and animation protocol in the Unreal Engine 4. It's an extremely complex series of engineering ingenuity that allows the art engineers to utilize per-pixel shaders across high-poly meshes. The art team also swapped standard textures for the Unreal Engine 4's material layers right down to the pixel. since producing 4K or 8K textures would zap the memory budget and would bloat the game's size.
It seems like a lot of work (and it was) but it was all so that Arc System Works could make it where the art team could produce high-quality 3D models with the kind of fidelity one would find from hand-drawn cells used in cartoon animation production. Arc System Works originally used this method in the Unreal Engine 4 to produce Guilty Gear Xrd -SIGN-. This introduced gamers to a fighting game on a 2D plane using 3D characters that looked like they came right out of an anime. Additionally, 2D fighters allow for faster engagements than 3D fighters since the 2D plane locks the characters closer together, creating fast-paced frenetic fighters.
The team then took the time to animate the characters on a frame-by-frame basis using traditional key-frame animating similar to hand-drawn sprites. The animators did not use the auto frame-fill usually used for most key-frame animations. In 3D games there's automatic frame filling that takes place so that between every key-frame captured, there's a smooth transition between character movements. This is what gives 3D games that smooth and fluid look, and also helps with making characters move realistically with motion capture.
In the case of Guilty Gear Xrd and the upcoming Dragon Ball FighterZ, there is no auto fill for the animations. Instead, Arc System Works manually and only key-frames the animations that are supposed to be rendered to screen that imitate hand-drawn sprite animations. This gives the game the fast-paced look and feel of a hand-drawn cartoon or the old sprite-based 2D fighting games SNK and Capcom used to make, like before Street Fighter and King of Fighters went 3D.
The result is a game that looks identical to the cartoon and plays identical to old-school 2D fighters. The fighting game community is already extremely hyped about the game, and Bandai seems to be on the right path by pursuing the eSports community.
Don't worry, though, Bandai Namco is likely going to keep supporting the Dragon Ball Xenoverse series since it's so popular with the casual fans and is an extremely easy game to get into. Hardcore fighting fans will likely stick with Dragon Ball FighterZ.