OH REALLY?
So taking the Uzumaki clan seal and barrier arts to a WHOLE NEW level by CREATING FTG, one of the greatest if not the greatest space time jutsu (It took out iwa on its own) is not an intelligence feat right, because you can be totally dum and create such a complex technique using one of the most rare and difficult ninja arts in the world right?
And I'm sure that recreating the Tailed Beast Bomb at a level where humans can use it with their own chakra (rasengan) takes a really stupid person to do right, you totally wouldn't have to be clever to do that right?
Oh Oh and how about the fact that Itachi, despite being tobi's apprentice and being so close to him couldn't even figure out the secrete to Tobi's space time techs (tobi's own words to sasuke) but Konan and Minato figured it out, and Minato only did it with just a mere glance of the jutsu while he had to take care of the kyubi, protect the village, protect his son and wife, all that pressure and he figured out how to beat tobi in those few seconds and Itachi was stupid enough to think that a mere amaterusu would be enough when he implanted the jutsu into sasuke, which didn't even injure tobi whereas both konan and Minato did.
Oh and I suppose you don't have to be clever to have the ability to completely analyse a jutsu's strengths and weaknesses and how to improve it with a mere glance like he did when Kakashi first revealed his raikiri to him, and against tobi?.
To create a seal that allows you to summon the shinigami (3rd admitted that Minato created it) and then use it to weaken your the kyubi by sealing away its ying chakra so that your son can have a better chance to control it in the future, to seal away your wife inside the blonde and yourself so that you can help him at the right moments when he needs you the most in the future, Minato did all of this, fought tobi and the kyubi, figured out Tobi's connection to madara in mere seconds, figured out tobi's jutsu in mere seconds, planned the kyubi's demise, protected the village and planned his son and the worls's future in that short span of time under all that pressure, dude can you comprehend the intelligence and foresight that this man has for all his feats, and the level of intwlligence he must have had to create all these awesome techs and to surpass the great Uzumaki clan in what is considered the most difficult arts to learn and comprehend?
Not to mention that it took Jiraiya till he was onliterally dead to figure out who was the child of prophesy but Minato was able to make a quick analysis and figure out that Tobi was the great evil and that given the circumstances and the nature of the prophesy, his son would have tpo be that child.
Minato is by far the most intelligent guy in the manga, the people that say Itachi are fools, Itachi couldn't even foll tobi and zetsu, they saw straight through all his lies and deception like an open book, just because he outsmarted sasuke that doesn't make him the most intelligent person.
And figuring out the secrete to chibaku tensei? Please, Naruto spoonfed him everything he knew about that Jutsu before he figured out Its weakness, he had to ASK naruto about it before he figured it out, in other words, he had INTEL, Minato figured things out without someone spoon feeding him, Itachi is just like shikamaru, he needs intel to figure out them things.
Itachi couldn't even figure out how to beat Tobi and Konan figured it out up to the most minute detail, even figuring out the time gaps and what he could and couldn't do at certain times with his techs, but Itachi, his apprentice couldn't figure out shit, because otherwise he would have, as Tobi said, been able to kill him and would have know amaterusu wouldn't do the job.
1) MINATO
2)KONAN
3) TOBI
4)Kabuto
5)Itachi/Nagato
6) Kakashi/Sasuke/shikaku/shikamaru/Hiruzen