No other bulkey waters mind burns more than Milotic does. Burns help Milotic wall physical attackers better but not by much as the loss of HP sucks. I wouldn't make this a reason why Milotic is a "better" heatran counter, just mention recover i think.Milotic is the best of these, as it has Recover, and doesn't mind Burns.
Mention Choice Scarf on the Stealth Rock and Explode set, or maybe mention stealth rock on the Scarf Set, it is a viable set that I have seen running around. Only Set Comments though, obviously.