Im hardly part of the Ace fanclub, but the power scaling here on your part is a bit out of proportion. Ace is a WB commander like it or not and that means that he is one of the most top class pirates. Ace prior to even being a WB commander was offered a position as shichibukai. Consider some growth from that time until the time of his death puts him at top Shichibukai level. When he briefly fought aokiji he did much better than doffy, managing to hold off aokiji and even melt some of his attacks.. Now I am not saying that doffy would lose to ace, but what i am saying is that he did significantly better is his brief time confronting aokji than doffy did who was frozen instantly and then retreated because he didnt want to fight.
Luffy is not better than doffy currently. G4 puts him quite close but without law, luffy would not beat doffy. Doffy has taken some damage from G4 but it isnt crippling him yet. The fight has yet to play out all the way but it is far to early to say that luffy could take doffy solo and much too early to say that luffy has surpassed ace. Ace was not weak despite what anyone says. He has the highest bounty in the series to be revealed thus far and putting luffy above that when there is still 10 years or so left in OP makes no sense. It was said that after 300 million the bounties get extremely hard to increase. This event with doffy is hardly suitable to raise luffys bounty by more than 100 million. Aces bounty being 550 million.
Also ace was only one shotted because he was protecting luffy. He woulda got beat by akainu pretty easily but he would not have been one shotted if not for akainu targeting luffy.