Minato looked directly into Obito's eyes, and if your gonna claim that Minato won't look into Sasuke's eyes for god knows what reason then Sasuke can use Amaterasu and Minato won't know since he isn't looking at Sasuke's eyes. Minato having more than Rasengan and FTG is an assumption.
Sasuke>Alive Minato
Edo Minato>Sasuke because Sasuke has no sealing techs.
In case you're not aware, Itachi's not the only resident genius around. Minato's a sensor, and was able to detect Naruto gaining control of Kyuubi chakra without touching the ground. Besides, his reflexes are good enough to freaking throw a kunai behind an incoming A.
If you're not ready to believe Minato can have other techs, fine. That still doesn't cut it, Tsunade was able to break Madara's Susanoo ribs with her punch, and speaking theoretically, Rasengan is a grinding attack, so if chidori is compared to a punch from Tsunade, and if we take into account how rasengan inflicted internal damage to that tank (Susanoo is somewhat similar to a tank, if you think about it, and Susanoo doesn't protect the user from damage inside susanoo, just from outside damage, proven from how Madara was pulled out of the Susanoo by Gaara's sand), then even his simple rasengan (which, btw, is far more powerful than naruto's odama rasengan) can damage Sasuke inside susanoo. Oh, I also forgot to mention that Minato had an elemental affinity that he wanted mix with the rasengan, and take to the highest level.
PS: About the looking in the eye part, Minato wasn't caught in a genjutsu by Obito though he looked at him in the eye now, was he? We still don't know if or not Minato has any counters towards genjutsu. If you're not ready to make an assumption that Minato has more techs (as I'm sure one doesn't become hokage with two techs, and only one offensive tech), then you can't make the assumption that he will get caught in a genjutsu, since he wasn't caught in one despite looking Obito in the eye.