For me it depends which Spam is the focus - is it down to Blockchain bloat or rewards?

All these dust accounts use space, but earn nothing compared to the alt-spam accounts being used by larger accounts just to reward themselves a little less obviously.

I'm for knocking a bit off payouts, perhaps even to the negative as @miniature-tiger suggests - that would help reduce space usage perhaps, but not the also sizable issue of larger accounts doing the old 1 sock 2 sock 3 sockpuppet routine.