The engine in Duke3dw is no different to the one in the other Duke3D ports, that's why I said it wouldn't be any faster. Missing endianness conversions don't cause performance hits, but they cause your software to malfunction.
If anything, it would make more sense to recompile the exitsting Duke3D port with the 060 compiler flag enabled. The current executable is compiled for 030. This includes the hand-written assembly, which is not even used in the Atari Falcon port.
Anyway, if someone thinks it's a worthwhile pursuit to make a classic Amiga port of Duke3dw, I'm not stopping them.