I think that some people are taking the hints too seriously for now. Especially in regards to the Admirals.
Sure, Aramaki fled, but he also reacted as: Fine fine, I get it, I don't want to pick a fight with you guys - Not yet at least
That's probably his character behaviour. Actually, all admirals apart from Sakazuki seem to behave kinda like this.
Kuzan was like: don't mind don't mind, don't want a fight right now.
Kizaru when fighting Rayleigh wasn't going at him seriously and up and left
Fujitora let pirates run away and didn't get overly involved - he could've squashed the alliance back in Dressrosa if he wanted - no way Law, Luffy and the gang would've escaped
And Aramaki did the same by playing around with the Samurai and then leaving after being blocked by Shanks
So far, the only instance where an Admiral has displayed full intent on fighting and killing his opponent was the war 2 years ago, and only Sakazuki was showing REAL intent on killing because that's how he is.
That being said, I wouldn't be surprised that other pirates, like Mihawk for example, can keep up with some of the admirals - not surprised at all.