I personally am not impressed. Removing the oxygen within a small area to catch people off guard. Now unless we assume that awakening removes the entire island's oxygen or covers it in deadly poison. Hakimen can break through being encapsulated in ice, but that wouldn't include being frozen to the core. And I think in terms of potency, Akainu is the best benchmark. The personification of Magma, most likely awakened and surely strong Haki on top of that, ending up severely injured and covered in frost bites by Kuzan's cold, who turned his side of the island into frozen wasteland and permanently changed weather as collateral damage.
Then you have Akainu who blows off heads and limbs and melts through organs with one blow, leaving Ace with a hole in his body and Whitebeard with a part of his head missing, while also having the power to alter the landscape into burning wasteland and volcanoes, to a point of burning ocean water.
But then again, yeah, if we assume an awakened gas fruit turns the entire landscape into oxygen free poisoned wasteland, that's another story.