I understand that they would never let us fully control a dragon to fly across the map (you can do it on PC with mod tools but that's better hardware any way). However, a few things:
1. It should have allowed us to use bows and crossbows, by allowing for a "zoomed" perspective. There are very few boss battles that even occur in the open air outside, and it would be harder shooting from a mobile air platform then simply running and shooting on foot.
2. The ability to tell the dragon when to use air combat and when to land and use melee/magic. Sometimes I want my dragon to chomp down, and some times I need it to strafe targets.
3. Better directional control of your shouts while riding the dragon. Honestly the only type of attack worth doing while mounting the dragon is magic, because those lock-on. With shouts you're dependent on fixed angles, which most of the time the dragon doesn't provide good ones at all so you end up shouting 45-60 degrees+ off target.
The good stuff:
1. I like how the dragon spots literally every living target in an area (I was laying waste to a forsworn camp and the dragon spotted some slaughter fish in a tiny pond 200 steps away, for instance). It doesn't fly far but it does do huge circling archs, so reasonably you can clear out any huge chunk of land.
2. You can still fast-travel while riding the dragon, so if you want to hop camps and fly to new areas, you can. You just can't fly DIRECTLY to that location.
3. Bend Will works on Odahviing, so even if you can't find a dragon to ride, you can call for one and then ride him around.
I'm at 81 on two characters so obviously there's no enemy that my dragon will kill faster then I will. But I'm well past "efficient killing" in this game, to me it's about fun, and at least for now I'm having a reasonable amount of fun wrecking enemies while dragon riding. I just wish they'd fix some of the glitches and make it more battle friendly.