I think I am about to do the unthinkable - Support Minato. Minato wins Mid Diff. The argument is rather simple here: he evades and remains on his toes.
Kakashi RSM is a one trick pony that will not last that long. His Kamui shurikens can be absolutely parried. They function to warp the objects on contact. All Minato has to do is spread his Kunais a bit far, which he can easily managed with his unrealistically stretchable BM chakra tails/arms. Then it's FTG or Body Flicker powered by one heck of a chakra to evade them.
Kakashi's Kamui doesn't extend to his PS, nor did he ever blitz anyone. Is this argument still going around? Also, we don't even know the amount of Chakra fueling this so-called mode. All we know is that Obito took out a tiny shred of it, enough to only make ONE, and I repeat One TSB. Now according to the Databook TSBs are made by a Combination of the Sage's Senjutsu and Tailed Beasts Chakra. Now how much chakra is fueling that PS? I would say it obviously doesn't compare to what Sasuke produced given the TSB that materialized. The chakra would be small by comparison.
All he has going for him is Kamui warp speed. Which isn't fast enough to prevent Minato from using FTG. He did it in the past and he would do it again. Other than Shurikens, his PS doesn't appear to have any other attacks anyway. One lone sword that did nothing. Minato can keep warping away and use Giant Rasangan through his Chakra Tails that he can extend to very long distances.
Even if it doesn't work, evasion definitely would. Kakashi's RSM lasted less than 2 minutes, and he isn't killing anyone in that time.