I mean I already bought it, so yeah I'm gonna get it. FF7 is my favorite game of all time, so I'm a bit invested in the game. In regards to your questions here is how I feel.
1. Combat - It looks busy but really isn't, based on the playable demo. If you play Crisis Core, it feels a lot like that. You can attack and block in real time kinda like kingdom hearts. But when you fill your ATB gauge you can pause combat and use a bigger ability or magic if you have materia equipped. Which basically turns the game into what a modern version of the ATB system would be from the original game. You can also assign abilities to shortcuts where you can quickly select an ability to use with your ATB gauge without pausing combat. So the game provides a lot of individual combat options for people and seems open to allowing players to play it in the way that best feels comfortable to them.
It's flashy, but there is less going on than it seems.
2. Parts - Nobody is really excited for this. But ultimately we cannot really judge how this feels until we get our hands on the full game and experience just how much content there is within this part of the game. They've said the game is going to be on 2 blu-ray discs and will have the same amount of content as a normal full Final Fantasy game. I'm a little skeptical on this aspect because I just don't see how they can take what was about 3 hours of content from the original game and expand it out to the point of being a normal 40 hour RPG.
Additionally I'm worried that if part 1 is only Midgar which was not even 5% of the original game, then how many fucking parts are they going to make for the remake? That's what concerns me. It taking 15 years to finish this damn thing. It wont stop me from playing whatever parts come out though so I guess I'm more eager to play even a partial remake of this game, than not play it at all.
3. Character Leveling - This is probably just going to work independently of each part. Like in Final Fantasy 13's three parts, they were all part of the same story with the same characters (kind of) but each part started you at level 1 like it was a brand new game. What concerns me is that Materia leveling in the original game was a big part of progression, needing to master each materia in order to not only gain more copies of a given materia, but also needing them to gain Master Materia's to give character's every spell, summon, and command. I don't know how this is going to work in a split up game, and chances are it'll just be gone.
When you remember FF7 you remember how huge the game felt, and thinking on the scope of what you played in 1997, you wnder how the hell would they make such a huge game work in a full modern AAA remake. However if you really break FF7 down, it isn't really that big of a game. We have plenty modern games that have worlds just as big or just as much content. Red Dead 2, Assassin's Creed Odyssey, The Witcher 3, etc.
I think what they should do is NOT try and make the world map a huge open world experience, but instead do a modern take on the scaled top down map itself and worry more about crafting the important areas. FF7 wasn't an open world game, the open world itself didn't have anything special in it except a few combat encounters like the Zolom, and the weapons, but otherwise it was just a map used to go from location to location. And if they keep that aspect of it, they can save a lot of meaningless effort and redirect it into the aspects of the game that mattered more.
I'm very hopeful for the game and very excited to play it. Even if it becomes a completely different experience, it will be nice to play in that world with those characters again.