I see several flaws to your argument. It will give the impression of a fanboy, but honestly he cant nullify FTG as easily as you assume, and given that, FTG can counter several of your +1 to tobirama. Taijutsu...minato would most likely know tobirama would win with taijutsu, so he would simply plant seals all around the area, if tobirama used a tech to wash them away, minato has the base speed to move in on the opening and get him. You also spoke of his lightning sword...i dont believe when it was referenced, it said anything about being able to halt a S/T jutsu like FTG, so unless the shock rendered minato unconscious, he could once again FTG out of the rings of electricity. As i see it, thats +1 minato, not tobirama(5-4). On to ninjutsu, while tobirama is all powerful with the water, Minato could too easily place seals out of range and if he gets into trouble, teleport out and back in to try a new tactic. And if tobirama uses a water wall around himself, it can become a war of attrition at that point, mniato standing there, tobirama standing there burning some chakra holding the wall up. I see that as a draw simply because while tobirama has him beat in actual ninjutsu, i see no reason why minato cant avoid all of his attacks. And lastly the summons. Yes, the ET summons were formidable, but you have to think, while unkillable, they wouldnt be the all powerful ET's like kabuto has in use now, it took him and oro much research and experimenting to get them vastly improved over their living selves. Also, i know you are breaking them into single catagories, but i feel that is an unusable style when talking about powerful kages as these fighting, it has to be the combo of all, and as you yourself stated, minato is a master sealer. All minato has to do is get a hand on an ET and he will seal them, nullifying them. And even if tobirama had thousands of strong ninja to summon, minato could seal them as quickly as they spawn. Based on common sense of the actual battle and not just comparing one stat at a time, i see minato taking it. Dont get me wrong, tobirama is amazing and id love to learn more about the powerful kage, but in a practical battle, FTG in my eyes over powers several of the stats you threw to tobirama.