The guy was a talented ninja prodigy that only came around once in a generation, one of the most gifted shinobi who ever lived; and one of the strongest shinobi that ever existed. His intelligence is probably top 3-5 in the series, fastest shinobi ever (not sure if Naruto has surpassed him yet). He absolutely pwnd Tobi in less than 2 minutes, arguably with ease. So opponents stronger than Tobi would be given a good fight by Minato.
It's easy to overestimate him because of how he has been described, especially with an OP technique like FTG. But I think alot of people just like to hate on him because of the fans, considering he is one of the most likable characters you will see in the series, I find it strange that a good character like him can get so much hate. Because of this hate people like to underestimate him too, before everyone I knew, knew for a fact as the 4th he was > 3rd - now for some reason this is in doubt. People say he will be stomped by Itachi and Nagato when that isn't true at all, he could win or lose to either of the two.
I still believe he is one of the strongest in the series, top 10 for sure (even top 8 at the very least in my book). Plus people forget that we've only seen about 3 jutsu from Minato, I know for a fact that's not all he has to offer, yet people compare him to OP characters with tons of jutsu. Not all of Minato's true potential/all his abilities have been seen so I find it absurd when people unfairly say he can't do certain things or won't beat x or y characters, yet a bit of hype for one character ie Hashi and then everyone sways to that side.
I know for a fact he is one of the strongest and can be overrated in the most stupidest ways at times but also he is underrated in the most unfair ways too. I just hope people stop hating him so much just because of others actions.