Well, I've been appreciating the game a lot more when I replayed it recently. There's a whole lot to love, but also things that need some fixing.
I don't expect that the sequel will throw out a lot of the stuff I disliked, but at the very least I'd like there to be far less hand-holding (or an option to turn it off). For example, I don't need to be reminded what button helps me grip onto a shaking Titan or re-balances me on a beam. They're always the same button dammit; I don't have Alzheimer's.
Also the QTEs (you know they aren't going anywhere) should take a cue from God Hand. That is, don't make them something you MUST succeed at or die, but have them be an opportunity to amp up the damage on certain attacks; for example, part of a combo ending with Gabriel/other Belmont ending with a thing which has button mashing that increases hits and damage, like Dante's Million Stab in DMC3. Obviously with less silliness than those games, but this would make them far less obnoxious and -dare I say it?- more entertaining.
For the music, as I've said in other threads, a good way to keep its unique style without throwing it out the window would be making stage specific themes, rather than the sets of three songs that just looped through each other with each death.