Unofficially, based on my review of the pricing and specs, the MS130 will replace the MS120. MS130 gig only all appear to be cheaper than the same capacity MS120s at List and essentially the same switching specs with slightly better power consumption. Of course your price is determined by your Cisco Account Team and Partner. The MS125s are harder to evaluate as 10Gb uplinks are only in the X models. I would suspect the 125s will live on longer.
However, officially, I haven't seen any answers to this.
I would expect a blog post or some other announcement later today with perhaps a few more surprises. It's still somewhat early at Meraki HQ.