I want to agree with you!
Writing software specificly for the Amiga is the best way to go amiga wise, using the best out of the hardware available.
There is a huge BUT to this though, how many people are you targetting ? Less than 5% of the whole computer community. Besides, the Amiga is strong enough the handle the direct port of the Windows version, and aiming at a 200 MHz machine is really not asking alot these days. Currently this means you'll need the PPC and hey,.. we happen to have one.

Nevertheless I agree it performs like {bleep} on my 040 aswell and I was dissapointed 2. Therefor I will try to make a lite version using more amiga specific parts.
Cheers!