According to a job listing, Warcraft III and Diablo 2 may receive a remaster treatment in the near future. Blizzard has been looking for a Senior Software Engineer and according to this job listing, Blizzard will be restoring Warcraft III, StarCraft and Diablo 2 to glory.
We already know that StarCraft will receive a remaster later this Summer, so our guess is that both Warcraft III and Diablo 2 will get a remastered treatment.
Still, we cannot exclude the possibility of a simple re-release (that works on modern-day operating systems).
Naturally, Blizzard has not commented yet on this, however we are pretty sure that the company will reveal these projects sooner than later.