They could add a stamina point system which is really just spell slots, but for physical. Physical can be the three categories: slashing, blunt, pierce. Some characters can simply use multi resources like superior die and ki for the more potent abilites. Keep the simple subclasses for new players but rework or simply add new subclasses with higher complexity. The animations and sound effects are the biggest things that need work. Needs kendo, fencing, and martial arts influencing. Exaggerated of course. It is fantasy after all.
Magic still with have fire, ice, lighting, radiant, necro, etc. So no it wont be homogenize the classes. Caster lovers will still complain I can imagine.
I LOVE the simple realistic animations and sound effects this game has. It gives it a less cartoon and more realistic feel, like you can imagine this world being real, and your not just watching a animated tv program.
If they take your advice and make it all exaggerated and loud, they will ruin this game from a masterpiece to just another video game, like so many other games out there.