Here's something I've just realized... on the DS, FPS games allowed you to use either the dpad or the four face buttons to control your character, because your dominant hand would hold the stylus. But on the 3DS, character control will likely be given to the slide pad... which is only on one side.

2012 has come early!

Here's a thought. Try playing FPS games on Wii where you get to use a TV screen instead of dinky handheld screens and can hold the Wiimote in your left hand with the nunchuck in your right hand.

This is something quite a few people realized. More of the people realized it because of Kid Icarus' described control scheme, that was very lefty-unfriendly. Though, it still stands to reason that a left handed person could use the touch-screen as the virtual analog stick for movement (much like on early DS games, and many iPhone games) and the analog slider to aim and be fairly accommodated.

No reason at all for that, sir. Some people like a little FPSing on the go.

This has been brought up before. It did not end well. That said, there's no reason why they couldn't allow lefties to still use the ABXY buttons as they have in the past. after all, there's still the d-pad on the left side for righties.