From my perspective ideally super speed would continue to stack with other stealth powers.
I use SS on all of my characters (they feel stuck in the mud without it), and I set up all my characters to have sufficient stealth to be PvE invis for most mobs. So, SS + Stealth IO, *OR* SS + some other stealth power like Storms steamy mist, or Cold's fog power (arctic fog? I don't remember the name), or dark armor's stealth toggle (cloak of darkness?).
With this change I can no longer do the latter. So I will end up doing a respec and burning a slot for a stealth IO on my characters with Storm, or Cold or DA. Not the end of the world, but given this change is supposed to be a QoL change, it is frustrating that super speed is being nerfed in the process.