You're cutting yourselves out of a fairly big market (3d printing) by not supporting STL as an output format. Ok you can convert it but it's extra messing about and with 3d printing there tends to be more iterations so it's more of a nuisance.

32 bit software can still be multi threaded (AKA multiple CPU / core support) - it's the memory usage that's limited. Again, no mutli core support is a big minus. With most decent quality PCs coming with 4 cores or more a single threaded program will only be using a quarter of the available processing power (my work PC has 16 cores so running a single threaded program is a bit of a waste).