Unfortunately that is pure speculation. We cannot assume that suiton is Minatos weakness. That would be like me saying that rasengan is Tobiramas weakness. It's a completely unsupported assertion. Also you must realize that kishi might not be done revealing their arsenals. I highly doubt that FTG and S/T jutsu are the only thing Minato can do. At the same time I cannot speak with absolute certainty that he does have other jutsus. As I try to remind everyone before speaking with certainty about a character be sure that the character has been completely developed before making your argument about who is stronger or better. Otherwise you could end up with a foot in your mouth later on.
