Did motiv go away from putting special outer cores in their balls?  Was there anything to this or was it just something to differentiate themselves from other brands when they first started out?

They still may use the Reverb outer core and just not advertise it like they used to.  Not sure though.

I think this hits the nail on the head. I think they stopped advertising it when they went to the white background on the sales sheets, as they stopped advertising neomark graphics. I can't imagine them abandoning a technology or strategy that got them as far along as they've gotten.

Matt