I'm pretty sure someone already tried to do it and never finished it. I might be wrong.
@ slimK: Everyone has his preferences. He wants the game to be more fantasy-like.
Then just buy new components or a whole new computer. They aren't that expensive nowadays. I've spend 850Euros for mine which is able to run Battlefield 3 on highest settings.
I'm pretty sure someone already tried to do it and never finished it. I might be wrong.
Flacko and I, along with other people, worked on a MOBA mod which was intended to be customisable enough to create a copy of LoL even though the default settings made it a copy of Dota 2.
We made towers, mobs, heroes and powers, but, as you said, we never finished it. We figured it didn't have the proper audience in CS2D - MOBA matches last dozens of minutes; collecting 10 players who can play CS2D for that long might prove to be somewhat difficult.
CS2D is made for quick games; in Tibia RPG you can play for one minute at a time and still have fun. A MOBA match with a team that changes its players completely every two minutes is strange, to say the least.