Why one earth would you want Warcraft 2? The races were basically just copies of one another. You can remaster the campaign if you want. Heck just throw Warcraft 2 and 3 campaigns back to back in a remastered package.
Because the game was fun. Most people would scream rose-tinted glasses, but I recently went back and played through the campaign again and spent a considerable time on skirmish maps. I think this was shortly after Warcraft the movie was released and my girlfriend wanted to play the games. Since the movie came out, I've been playing it off and on along with Brood Wars Remastered.
The popular rumor was D2 was getting a remaster before WC3, but again, it's purely speculation. I haven't been keeping up, but if DotA 2 uses a new engine, they could easily remaster WC3 long before D2.