I don't know if I want them to develop a new Suikoden or not. It breaks my heart to say that but I have a feeling they would not do the series justice. I would love to be proven wrong.
Suikoden 3 would be a great game to remaster if they respect all the original style, which was gorgeous. It was a very ambitious game and it perhaps tried a few things before the technology was ready. I loved the game, one of my favorite games ever, but it had some rough spots.
Suikoden 4 could straight-up use a remake.