if he didn't have haki he wouldn't last 1 second in the new world he was really respected there and was the second in command in the whitebeard pirates
Caesar Clown and Monet say shut up.
Ace didn't have Armament per his portrayal so far.
Ace did lose to Akainu, his powers are completely ineffective against Akainu, how would he put up a good fight? Akainu roflcurbstomps Ace 10/10 times.
so you think that someone whit the the bounty of 550 000 000 (and yes i know it doesn't mean strength) has no haki .
even when he saw luffy doing it he said you too come on don't be stupid
Ace had such a high bounty because he:
1. Kept getting into fights
2. Was the son of Roger
3. Was a commander on the most dangerous pirate's crew
Haki could have, and most likely didn't, have anything to do with Ace's bounty. Ace has had ample opportunities to use Armament, Observation, and his Conqueror's, but never did, showing he wasn't a master of Haki.