As it turns out Zebulon had a run-in with a shifter who really knew how to use his class abilities. As he was flying back from Skettis daily questing high above Terorkkar Forest, Zebulon, who was playing a Rogue, was ambushed by a Druid in Swift Flight Form. The attacker flew above him and shifted into caster form. The Druid cast Insect Swarm and began spamming Moonfire as he dropped toward the ground. The altitude permitted the Druid to break combat and return to flight form. Because of the speed boost from epic flight form the Druid was able to make another pass. Damaged, dotted, and desperate, Zebulon searched for a safe body of water to drop into. The plan was to dismount into the water, Cloak of Shadows, and then Vanish from the attacker. No luck- HK for the Druid.
My concern is not for my friend. Zebulon is a mean, nasty ganker. He certainly got what he deserved. The real issue is that Druids are the only characters that are viable in aerial combat. This is because flight form is an instant cast. Mages may be able to drop an instant spell or two and then Blink safely to the ground. They would not be able to reengage the target because the casting time for the flying mount is three seconds and can't be done while falling.
What do you think? Is this a terrain exploit? If it's unfair, how could it be resolved?