If Square were to remake FFVII they would have to go all out. New battle system and everything. They would also have to be careful not to alienate FFVII's fans and keep its nostalgic feel to keep everyone happy.

Its a daunting task so no wonder Square are hesitant to make it. But it'll still generate a ton of cash, bad or not. So Square will always be thinking about it and are probably thinking of ideas and concepts for it everyday. Waiting for the moment they have everything right to announce it. And then the internet explodes.