to make an OW from this game, you would have a re-think about the gameplay, combat mechanic and the core game it self. or else you will end up with a 500Go unplayable game.
However it would be easier to keep simple thing as cosmetics, some combat features and rebuild from (near) scratch.

but a game with those graphics and spirit could be cool. And as the code is a spaghetti code, making a "new" game should'nt be that hard compare to make a new update (i'm not even talking about a massive one).

The game
could work similar to Elseword. Various lobbies signifying different locations and still have the pvp aspect but they Dev's long sincese sunk any and all goodwill.