Lots of good ideas here. I like most of the ACC cast, though Aerith's VA from Crisis Core did seem better than Suvari. Though as has been mentioned, part of ACC's VA issues I think stem from SE not bothering to reanimate the mouth movements to fit English dialogue. Hence we have moments like dilly dally shilly shally and Barret's weird grunt after "You look after Mother!" which itself was a bit of an awkward line, I thought. Also, if they ever re-release ACC, I hope they do a true HD version rather than just part HD and part upscaled and translate the Japanese text at the beginning scenes. That always bugged me that they never did that.
Anyway, sorry for getting off topic. I can definitely see Sutherland as President Shinra, or perhaps Patrick Stewart. I think Cary-Hiroyuki Tagawa (Shang Tsung from Mortal Kombat) would be perfect to voice Hojo. He definitely can give his voice that sinister edge, and it's far better than that whiny cartoonish voice we got in Dirge. I think a darker voice, properly understated but very much there, could make Hojo a much more effective villian and character. One other possibility that could pull it off quite well would be Tim Curry - he excels at playing villians and has done VA in games before (Arl Howe in Dragon Age: Origins).
And definitely bring back Quentin for Reno, and Rick Gomez (I think that was his name) for Zack. Newburn was fine as Sephiroth, I thought, though it took me quite a while to realize that this was the same guy that played Brian Mackenzie, Annie Banks' fiancee, in Father of the Bride. I think he must have lowered his voice an octave or something to play Seph. And if Jenova has any more lines than just the one from the OG, I think Claudia Black would be a good choice for her voice.