I think that adding a bit of rpg gives homage to the original gbf. Also, seeing the monsters in combat adds a bit more flavour in terms of what people would say as a fighting/action game. You are fighting so there should be plenty of permutations. Tying both fighting and rpg elements can be difficult! Since finding common ground between the two gameplay styles would not likely hurt the two factors, it can be a note to keep in mind. Something like visuals, where subtle things like (optional) weather changes could enhance the product. Of course, maybe having platforms, field effects (meteorite showers, fog, smog, heavy random wind, eroding sand storms, wrath of thunderstorms?, random earthquakes, etc), and possibly environmental interaction (maybe forage some skill cooldownish herbs) would be some ideas laying around.
In terms of manga aesthetics, I admit that in most games, you will never ever see a vivid animated title with the aesthetics of a focused still portrait polish. Animation was the key focus to keep things moving, but you see, the colours, or even the rendering and style used, was sacrificed/compromised greatly, losing its visual luster. You know, you see the blobs replacing hairlines in most animations. Gbf: vs is definitely an attempt, but to even emulate the finest ingrained detail of a portrait appearance while in animation is of a nigh unreachable technical requirement. You will need professional work with all resources and assets beyond a normal timely budget. Even then, the output in maintained highest quality would probably be small video clips.
Still, as the gameplay itself, I am sure the design and implementation will work out. The visuals will be acceptable, but it's the style that would count. Although, I am not sure if there is anything groundbreaking yet (asides from the visual integration). It's probably better to wait and see for the recipes.