I was forgetting about flight paths.
Let's delve on that a little bit.
Flight Paths let you travel from point A to point B.
I don't consider that skipping content - not in the sense I do when I mention Flying Mounts.
Flying mounts letting you travel from point A to point B is NOT a problem.
Flying mounts letting you explore is NOT a problem.
Flying Mounts letting you get the reward without overcoming the challenge IS a problem.
Flight Paths can't do this.
Flying Mounts completely defeating the idea of fairplay by letting you cherry-pick every opponent IS a problem.
Flight Paths can't do this.
Flying Mounts making Ground Mounts pointless IS a problem.
Flight Paths don't do this either.
But I disagree when you say that Flying Travel will never be balanced with Ground Travel.
So what exactly are the problematic characteristics of flying? How to change them?
With just the 4 ideas above, you'd already have fairly balanced mount mechanics.
You wouldn't just blindly go through trees or hit walls like it's nobody's business.
Flying would be great (even better than now) for traveling large distances and crossing entire zones.
But you wouldn't land like a lightning bolt anymore.