There seems to be no fixed pattern for the Zsnes hanging issues with ROLW as far as I can tell, and it is that level of unpredictability that is the crux of the problem. I'm not tech savvy enough to pinpoint what it could be, but in my experience a few games have a lot of issues running correctly; Slayers, Shin Megami Tensei, Actraiser 2 and ROLW itself present either intermittent hangs or saving problems.
That said, the emulator indeed raised the bar very high for a long time, and it became a sort of hallmark emulation-wise, given the complexities of the target system, so I'm not trying to bash it or anything as it has been my SNES emulator of choice for a long, long time.
Also thank you for your kind words, Mr. Bing. I'm not sure if ROLW's localization would have been history-changing, as you purport but what I do know is that the west has missed (and still does miss) a lot of quality games due to various industry policies and profit considerations. The essence of fan translation groups, as I see it, is trying to lessen this disparity by bringing to the greater public games that the group members believe can and should be appreciated.