If it was the entire series
If it got rid of the card mechanics of CoM and tweaked the story to remove the padding (or summary of the previous game, depending on whether you were part of the 1st targeted audience that was to get caught up on the game or the second one that wanted a continuation)
If 358/2 was reworked in terms of leveling and in trapped area missions
If BbS's difficulty could be a tad more forgiving
If RE:coded wasn't the result of 2's sequel twist
I would think about buying it then
If everything after the first game was Word-of-God-ed into an alternate continuity, then I'd definitely think harder about it.
If the next game was promised to not be about the main cast, didn't retread the same areas, people, and events, decided to look at things from the Darkness side of things, had better antagonists than most of the series(if you picked up the previous suggestion, you could have a Light-side fanatic trying to fuse the worlds and destroy all emotions or something like that, so long as he doesn't retcon something and doesn't try to fulfill both villain roles the first game laid out like Org. 13 did), and if the male/female ratio was more evened out so I didn't hear yaoi fangirls all the time when I played, I'd definitely think about giving more money to the series to continue.
As it is though, I'd probably only care about a console version of BbS and a rerelease of the first (and the second only if it's bundled with that).