RTF is a global modification that replaces all towns in the game.

How much does it weigh? I mean, in terms of triangles... or are the models in Warcraft similar in polygon count to those in Heroes?

No, Warcraft was released relatively recently – I have a knightess model without a horse on my desktop, and it has 20,000 triangles. I don't know how many polygons my other details have; I only reduced the detail on the head because the detail there was noticeable – from 4,000 to 1,300, and then I also removed the teeth, mouth, and back of the eyes.

Added 1 minute ago
Of course, Warcraft also has LOD variations.