Ha, IDA for OS X with a GUI won't happen unfortunately (much as some of us would hope). It can run in Wine, but IDA in Wine debugging anything running in Wine is anything but successful usually (not to mention the trouble of getting a Wine build for OS X that works right). Sorry to hear of a lack of PC though, Hyper.
As for Assembler, yes, it does have some nice advantages to it. Difficult to learn, but certainly worthwhile and definitely a requirement when working on older software and/or with older hardware. I haven't shoved a C&C EXE into IDA, but I'm guessing the code's definitely a rat's nest of fun to work with, right? Out of curiosity, what compiler?