It's disappointing that it seems to be going the full light gun route.

Don't write off light gun games. There's some good ones out there, so the genre itself is not bad; it's just that the people making them actually understand how to make games!

See, if you start with an FPS as the base, it's about 2 things really:

1. Moving through 3D space
2. Shooting stuff

So if you make your player hold a gun, as of now this doesn't leave hands free to look and move, so these games moved for you on rails. However, because this portion has been simplified, they instead ramped up the shooting portion. Aiming and firing a gun for real is challenging, so these games had tons of enemies, they pop out quickly and brutally, and often times you'd have to shoot the projectiles they fire at you to stay alive, manage your ammo and reload at the appropriate time, not hit innocent civilians, etc. They understood that if you simplify one portion, you have to make the other portion more complex.

But if you're just going to tap a place on the screen to shoot, you are making the shooting portion less complex. Have you ever played duck hunt sitting right next to the TV, pressing the gun against the screen to easily shoot the ducks? You get to level 99 and it loses all challenge. You utterly ruin the game.

In five minutes I knew this was a bad idea, which shocks me that professionals (who are Bungie alum no less) don't see it.

Extra Credits is right in their episode about touch screen gaming: you need to really think about using it properly. As far as touch screens go, I think the following genres would be enhanced:

1. Turn based Strategy.
These games often take place on a grid, and using gestures to scroll / rotate the camera, select units and structures, and choosing actions from a menu would be completely natural.

2. JRPG
In much the same way, instead of using a menu to scroll through attack / spell choices, just touch. Outside of battle, you press where you want your character to go. Dialogue boxes could be scrolled through with swiping.

3. SIM
Sim City type games would be badass. Draw roads and zones by dragging your finger, swipe to move the camera around, pinch to zoom the camera in and out, 2 finger rotate to rotate the camera etc.

4. Adventure
Menu driven or point and click adventure games are perfectly suited for touch screens.

5. Hack and Slash
With some work and a good developer, this might be good. Have your character skills in a bar on the bottom, tap one to select it, and tap the enemy to use it. Could be just as easy as using hotkeys and the mouse.

6. Puzzle
Puzzle games, like adventure games, are perfectly suited for touch screens.

7. Rhythm action

I can see rhythm action games working, since tapping the screen on the beat is really no different than tapping a button to the beat.

That's it I think. Everything else, and you are handicapping your game.