And I'm just sitting here playing banjo kazooie, on a serious note if you haven't played banjo kazooie before let me break down the mechanics for you:
- Flight pads trigger flight (they are in most levels designed to have flying but not all)
- You needed red feathers (a collectable consumed over time) to keep flying
- You naturally glide downward
- To fly higher you used additional red feathers (flapping your wings)
- You could shuttle yourself a long distance while flying for additional red feathers (if you hit things that don't take damage you'll take damage and stop flying plummeting to your death)
- If you landed you stopped flying
Since flight in Banjo has its limitations there's a lot you can design with it, you naturally can't use it forever as you'll run out of red feathers eventually, you can't use it to hop from objective to objective since touching down grounds you, it brings a lot of value to the ability because it is limited, while at the same time not making ground movement redundant just different.
Some people are bound to say "but I like to have complete and unrestricted control of flying at all times, moving at 3 times the speed and ignoring everything I don't want to interact with", me too man, me too. But this is simply avenging wrath 100% of the time with no CD, it is simply a redundancy that increases game play efficiency and not depth. Avenging Wrath 100% of the time with no CD is bullshit the same way unrestricted flight is.
Blizzard could turn flight into a mechanic, but that would take effort and raid dollars.