Except that wasn't Degica, that was Agetec for consoles and it was INCREDIBLY limited. If you want Ace potential with 3D, it will cost a lot. Also, making assets for 3D and using a 3D editor is far more complicated than using a 2D editor. Besides, the 3D Game Maker market on PC is covered. 2D is where it's at for RPG Maker. (And 2D RPGs are way better anyway). If you go to a 3D maker, unless you're pumping out FFXIII models, don't even bother. 2D Makers on the other hand, it's not as difficult to make good looking assets.
Actually it was the most feature-rich of the console RPG Makers, so much so that it's massive load of obscure and complex features was one of the reasons why it didn't sell. It was actually about as functional as VX Ace, just extremely non-user-friendly and cumbersome. It was even possible to make custom 3D models with it (although they were really just bundles of visual effects), and I evented together a fully functional FPS with it in 3 days. And yes, there were guns.
Also, I've used 3D editing software before, and, while it can be complicated when it comes to lighting and effects, it isn't that much more difficult than 2D software. Animation, for example, is a lot easier and less costly in 3D. Being a decent artist; however, is a requirement. A 3D PC RPG Maker is very possible to make both feature-rich and functional, is what I'm saying. The only problem I can see for it is that most people don't have PCs that can handle highly complex 3D without slowdown or crashes and that the filesize of a finished project might be huge, so there would be less game-trading and sales in general for it.
I think you might have been thinking of RPG Maker 3, which was extremely limiting, to the point that it wouldn't allow you to do things like
change the regular battle music.
As far as a 3D editor goes, though, the feature breakdown would probably have to be something like this:
Outside Editor:
-3D Models
-Textures
-Animations
In-Engine:
-Lighting effects
-Particle effects
-Scenes (as opposed to the mapping system)
-Actors
-Collision detection
-Allocation of animations to standard RPG tasks (Walking, Item use, Fleeing, Defending, Spell-casting, Jumping, etc.)
3D Specific Event Commands:
-Show animation (Shows a custom animation for the specified Player Character or Event)
-Change texture (Swaps textures on the specified for other custom textures)
-Move to point (Draw a path with a mouse/tablet through the scene on which you want the specified to move and specify the movement speed. U and D keys control elevation)
-Change default animation (Change a model's standard animations to other custom animations)
-Standard camera control functions
-Lighting control (Move and modify light sources around the scene)
-Show effect (Self explanatory)
-Change animation speed (Add a modifier to all animation speeds for the specified)
I think that's all the really basic stuff.