I don't think I could mod WC3. Not yet anyways. I might be able to make an OP2 map on WC3 though. And I'd probably lose interest half-way through becasue, unless WC3 has laser cannons, microwave pulse beams, rail gun projectors, rpg, esg, emp, stickyfoam, and acid cloud launchers, energy rifles, afrtifical lightning systems, starflares, supernovas, EMP Missiles, and space to put all of the possible buildings, vehicles, and research, it'd be quite near impossible.
In build/research menus that is.