If youre hoping for a straight remaster of D2 thats offline youre setting yourself up for a huge disappointment.
Its pretty much proven now that making games require online means both an increase in sales and a reduction in cheating/modding. Its also no great leap to assume that since WC3 is using battle.net, so will other remasters. But given the mess they apparently made of WC3 (dont play it myself so just going on what websites have reported), It would probly be better if D2 is left alone so we can continue to remember it fondly and not as a screwed-up mess.
Although that does raise the question of whether theres any game that has actually been remastered and recieved positively?