Leatherhead
Possibly a Idiot.
If anything, allowing flight to work in heavy armor would actually help STR focused Melee characters keep up with Ranged builds somewhat. After all, light armor + full DEX is only one AC behind heavy armor, and functionally better than medium armor due to the lack of a stealth penalty.
As for encounter design, flight would totally decimate ground-bound enemies in a "white room" featureless-plain-with-no-roof deathmatch. But on the other hand, who actually designs real encounters like that? You can include things like enemies with ranged attacks, a celling, trees, strong wind currents (for difficult terrain), hazardous gasses, raised wire traps, an ally that also needs to get across that pit, or a city that is going to be eaten by the Tarrasque if you don't stop physically impede them.
Furthermore, if you are flying and stopped somehow, you fall to the ground and take extra damage. Which makes it dangerous, Like if an arrow knocked you out, you are automatically down one death save from the fall damage, and possibly far away from any allies who could save you.
As for encounter design, flight would totally decimate ground-bound enemies in a "white room" featureless-plain-with-no-roof deathmatch. But on the other hand, who actually designs real encounters like that? You can include things like enemies with ranged attacks, a celling, trees, strong wind currents (for difficult terrain), hazardous gasses, raised wire traps, an ally that also needs to get across that pit, or a city that is going to be eaten by the Tarrasque if you don't stop physically impede them.
Furthermore, if you are flying and stopped somehow, you fall to the ground and take extra damage. Which makes it dangerous, Like if an arrow knocked you out, you are automatically down one death save from the fall damage, and possibly far away from any allies who could save you.