I'd love a remake, but I'd want more added TBH.
I don't think it'd be too hard to appease all sides either. I'd like to see more weapons / armour configs, break limits (and limit breaks I guess

), extra materia / enemy skills, optional stupid hard bosses like in FFX, monster arena(a la FFX) or similar, extra dungeons and towns, expanded current towns (I'd love to see more of Midgar), extra quests from townsfolk, expanded gold saucer, etc etc. (Note none of this changes story line).
But, make it totally optional. Allow the current game time-line and events to occur exactly as they do now, should the player wish. But, should they wish to spend more time grinding away getting bigger and better weapons, materia and levels, allow it. None of it would have to interfere with the original game mechanics (which I still love - and am currently playing

).
I also think summons would need to be re-thought. Its pretty redundant in FF7 as it is (apart from chocobo for a little while, which is handy. And Hades to pair with added effect and Phoenix with Final blow). They don't get equipped in my party at all. Again, maybe a more FFX / FFXIII approach where they become more of a party member.
I love FF7 for what it is, but if it was remade, I think it'd be mad not to add more non story-line content.