I think that Amnesia would take iOS gaming (iPad in particular) through the stratosphere! I would love the game to be ported to iOS. I have a question though, to people who are less of a novice than I am when it to processing power, is the A4 and / or A5 powerful enough to run a game like this (and at a smooth frame rate)?
Sadly no, while the graphics are not super advanced (still more than any of the current iDevices can handle, though the could be down-scaled possibly), Amnesia relies on a lot of physics for puzzle solving. This uses a lot of processing power on its own. I do agree though, movement aside, a lot of Amnesia would have played well with a touch screen. Not sure it would have packed the same punch in terms of terror though.
I think the game will actually work well on Touchscreen, the graphics are not too heavy, and the game mechanics should fit mobile, especially the iPad, or the 12.9 inch iPad Pro (since it is huge.)