The Steam PC download for FFVII is 1.2GB so I assume that Square Enix would have had enough space to develop it for iOS before now if they were planning on. The actual game size is around 1508MB.
Oddly this was my first reaction too. Thst said, 2gb was always enough to enable Square Enix to deliver FF7 to iOS if they really wanted to, so I wouldn't hold my breath.