TBH, Trick Room is non existing in Haxmons, as no one got time to set it up besides good scenario Cofagrigus sometimes, but Trick Room fails against common strategies like Flinch and Freeze, also Banded things are very uncommon as they are likely KO'd before they can do anything, maybe Scarf would be a problem, but it will give Omastar a free turn if it uses V-Create, if it uses Bolt Strike, I can play around it easily by probably foddering one and setup an agility on Lucario or so, or switch in Shedinja, which it can't hurt anymore.
Edit: As damage is halfed at Omastar, Heatran and Omastar are both equally weak to Bolt Strike