i.e. optional suffixes to highlight social gender, but the default was neuter? I'd like it better than the current system, but I think that the suffixes aren't even necessary - if you need to specify the gender, you can simply plop some additional word and call it a day.

That's a piece of criticism in retrospect though. Social awareness of gender issues was way lower in Zamenhof's times than now, not really blaming him.