Yep, mods are where its at, i like W3, just not the original gameplay. The engine is very versatile and allows for many different types of gameplay to be played. I personally like adverserial hero maps(DOTA, ToB, that other one...). StarCraft did this pretty well too, really liked playing madness maps in that.
Im pretty sure the reason for mods being so great is that theres exponentially more people to mod the game than make it, allowing for many more points of view and ideas to come into the game, and since the focus isnt on making money(for most...), it allows the developers to take their time and do things well.
The modders are from the community, so they will listen to it. many game developers do this, but i think they dont create the same relationship, because their companies ultimate goal is to make more money(hopefully by pleasing the customer right?).