SSU is just one of those things that gets more useful with gear progression.

Also if SPD on pets has been fixed then it will be highly effective. i.e. more pet attacks at a higher crit rate is a lot more procs especially from Ifrit who can proc SSU from AA damage.

SPD on SMN is kind of rough though so there isn't much point stacking it to any great benefit. 1000 SPD would give somewhere around 3% dot damage on a proc. So in that regard it would be nice to change it.