First off........FTG FTW!
Now, being able to move instantaneously makes you the best. Kinda like Goku. Maybe Goku couldn't overpower Cell like Gohan, but he sure could hit him at point blank range out of thin air. HUGE ADVANTAGE. Can't stress that enough.
Minato was not only fast, but again, could also move instantaneously. Like now you see him, albeit barely, now you don't. He carried bigger, heavier Kunai than everyone else because he was going to get behind you and needed to do MAX DAMAGE in one hit.
The same limitations he saw in Chidori for Kakashi pre-Sharingan, are the same limitations he'd have had with Rasengan without FTG. Naruto has clones and sleight of hand. Jiraiya had Sage Mode and Legendary Sannin Status. Minato had FTG. Pre-Orochi Sasuke both techniques required you to be up close and personal on your opponent to be useful which puts you at a disadvantage. With FTG it's a win-win situation.
Yes, that technique made him Hokage. Why? Because he was the deadliest ninja bar none. There was no Genjutsu involved or needed. Kinda like early Naruto, he's just going to come at you, but in his case, you really have no chance.