3d is kind of a double-edged sword. It really only helps you if you make use of it. What I'm looking for is something styled similar to an anime in pacing and presentation. There's a lot of things I won't be able to do, like talking animations or expressions or whatnot, even though a lot of that is critical to visual storytelling (and anime especially). So, it will definitely come down to defining a style and building around that. I've considered many different avenues, but ultimately the most painless is Unreal 4 due to how easy it is to translate content into it and how familiar I already am with many systems critical to any project.
Consider that a project like the one you linked requires exceptionally high skill in Ruby (RPGMaker is very heavily reliant on Ruby for anything beyond the absolute basics, and is why I didn't stick with it even though I worked with it for years in early 2000), and that presents a considerable roadblock.
As for matinee and the involved problems, I fear this is going to become a bit wordy.
Matinee is basically the cinematics editor of Unreal. The proper way of making a cinematic is to motion capture and then tune the resulting animations in 3ds max or whatnot, then bring them into Unreal as a composite asset that basically is your scene minus flash. Unreal adds the flash. Matinee is the track editor that handles everything from cameras to triggering sounds and particles and you can do all post processing in it, like color grading or slow-motion. Think of it as like the cutscene editor in sc2 but a lot more powerful. Unfortunately, it hasn't seen much update since Unreal 3, and it doesn't really interface with Blueprints (Unreal 4's replacement for scripting) which handle all the things like animation blending and fusing my various components together and ensuring they are synced. My cinematics will basically be a bunch of general gameplay animations stitched together in sequence with camera angles giving them context.
Taking a Tera asset as an example, I have to do a bit more than just attach body parts as a component and ensure they are synced. I have to do the equivalent of weighting bones to pieces from opposing meshes.
This spaghetti ensures that no seams appear in the neck as a result of differing weights between pieces of the head and body. It's the same as aligning and linking the bones in 3ds max. Without this, there are very large seams. This is a process specific to Tera assets. I haven't looked too heavily into assets from other games, but the theme of independent face animations is common and, without them, the head usually clips heavily.
Matinee cannot interface with animation blueprints, send commands to them, or even access skeletal mesh child components of an actor. I found mention of an update for Matinee being worked on in mid 2014, but like many things with Unreal 4, it is probably a long ways from being finished. I need to change my content at the source level to suit Matinee if I am to go this route.
Like I said, I have a few possible avenues I would need to test to verify if they would work. If they don't work it is very plausible I can fall back to Lineage 2 or WoW assets. The problem with that is less what I set the audience for, and more that I want consistency. My static meshes and particles are very high detail. I can update Lineage 2 monsters but characters are very dated looking. WoW is... not at all comparable to the asian games. I did experiment with changing WoW model proportions and bone weighting to sort of shift them into a more realistic style, but I didn't have a great deal of success. I could keep trying, I suppose. Though I need to get a CASC viewer and such.
I'd also probably have to reverse sc2 cinematic models and learn how to rig and animate them. I think that would have to be a long-term goal. Rigging and animation are two virtually inscalable walls... but learning either one of them would make this work so much less painful. I could, for example, weight the problematic Tera meshes to the Unreal base skeleton and dodge all of the issues related to components. Or I could weight them to WoW skeletons and alter the animations as necessary. I would probably focus on getting a simple animation setup down first before thinking about trying such difficult things, though. Unfortunately, Tera has no animations for single wielding a 1handed sword... which is something I really would need.
If I could get that working out I feel like I would be in free range territory. I have created materials from scratch that effectively translate texture information and builds higher detail and highly customizable variants out of them, and I have a super high quality skin material.
I did have success in sc2 with everything but the computer AI. I'm not currently considering a project for it, but I am going to ask quantum_menace some technical questions next I get the chance and see what he thinks. I can put the same assets in sc2 without too much trouble.