This is a good point, Amiga games in their original state do not translate well to touch screens
If the game concept is good it is better rewritten to take advantage of the modern interface 
If I'm really honest, my enthusiasm for an Amiga emulator on a modern smart phone has dropped to zero... The Amiga and it's software just were not designed with touchscreens in mind...
I would agree with this, but I am a fan of emulation.
I was thrilled with the C64 emulator when it first came out but it too sank to zero. The joystick control on it is just not work well for me. Sometimes I can see Bruce Lee because my thumb will block him so I'm trying to move it about and it just doesn't work well.
I fear the Amiga Emulator with its need for both mouse support and joystick support will be as awkward.
However, I have respect for the folks doing the emulators and I hope they keep coming out for every new digital device. :-)
Cheers!
-P