They are super cool! Look on Reverb. As I said, you sometimes end up with some fully licensed, expensive plugins as well. A lot of us can probably survive being a couple of versions behind.
I know for a fact new devices like this are on the horizon, but it just might not be the form factor that you are looking for.
For me the main issue is the VST-as-a-service model which is already taking over. I don't sub or micro-transact. The Roland VariOS thing I have had very expensive instruments too, luckily mine came with the CF card with all the ones which exist. I've never hooked my MPC up to the Internet to get VSTs either, I'm quite happy with what I have actually. I have been fiddling with electronic music for a long long time, and I remember when VSTs hit the scene, I got VST-itis and must have pirated everything under the sun but that leads to choice paralysis (same as getting all the MAME ROMs back in the day). Now I'm happier getting more out of what I have by using my brain a bit. Having generic USB MIDI on the MPC has been amazing though, everything is so much tighter without having to daisy-chain and even Roger Linn is impressed by how tight the timing is. 9 ins and outs is incredible, if I need more I just attach another generic USB MIDI interface.
It's actually a golden age for the MIDI fan but there's a lot of complaining to be done too about aspects of it. Cheapness and hooking you to a store being two big ones.