To answer the question, no, REV2 doesn't have poly aftertouch as far as I know.
About the use of poly AT, I personnally think it's great and way more usefull than "mono" AT.
In fact it's just like mono AT but with more possibilities.
I wish all synths would have it. Not because I use it on every song, but because it's always good to have more tools and options.
It's very easy to use and doesn't require any training, except if you want to do simultaneous independent modulations on each note, which I almost never do (because it's hard to master).
It's mostly usefull if you want to modulate only 1 of the notes you're playing.
Hydrasynth poly AT is extremelly good and fun. I find the AT on this synth way better than the one on sequential synths.
I encourage people to try the HS instore.
"To answer the question, no, REV2 doesn't have poly aftertouch as far as I know." Oh... but it DOES. The Rev2 does INDEED receive and respond to poly AT, just like the Prophet 08 does... Page 80 of the Rev2 manual, "1010 nnnn 0kkkkkkk 0vvvvvvv Polyphonic Key Pressure".
"It's very easy to use and doesn't require any training, except if you want to do simultaneous independent modulations on each note, which I almost never do (because it's hard to master)."
Yup, that's what I was trying to say. 2 layers split can accomplish this with channel pressure, if one only wants to add aftertouch to the lead, for instance. And the independent modulations being hard to master is exactly what I meant with developing new playing techniques/styles which would probably take years to do properly. That's what I meant by "poly AT isn't that big of a thing, GENERALLY", as there are channel pressure workarounds like layering to emulate the way poly AT is generally used.
On a single patch however, for ambient and other stuff, with a long release time, it's nice with poly AT, to be able to modulate only the note(s) that are still held or played, without affecting the decaying ones. I haven't found a strict channel aftertouch workaround for this yet, except by using an MPE controller to rotate between different midi channels for each consecutive key pressed, connected to a multi-timbral instrument, setup with the same patch to receive on all those channels. So if I set the MPE controller to cycle through 8 midi channels with channel aftertouch, and setup the receiving synth to receive on 8 different parts, each receiving on it's own dedicated midi channel, it can be emulated. Some multitimbral instruments have 16 parts, which makes for 16 notes at maximum. I admittedly don't have 16 fingers, but for long release times, to avoid note stealing, it could be useful.
And as Tugdual put it "I start thinking poly AT is totally a sound design thing." I agree in my own personal case, because of the "hard to master" aspect for true polyphonic AT playing, sound design is mostly what is usable to me, and the "long release" patches. I sold off my poly-AT Ensoniq keyboards, as I find MPE even more expressive and versatile when it comes to sound design. So I got a Sensel Morph instead for use with MPE apps like Moog Model15, Continua and others, and hardware like my old JV-2080. Even if the JV receives poly-AT, setting up as described above, cycling through midi channels on different parts, is even more versatile than AT alone, as each individual note can be modulated in both X and Y axis as well, not "just" Z (poly-AT).
There's also the TBMS ios app, which can be used as a poly-AT controller, where the developer implemented poly-AT with optional note on/off messages, on my request. This way, even released notes, with long release or held by sustain pedal, can STILL be independently modulated after release. So, for instance, for ambient sound design stuff like evolving chord "drones", I can use either an inverted sustain pedal behavior (so that pressing it sends a sustain OFF, and releasing it sends ON message), or a latching momentary switch as sustain pedal (with alternating ON/OFF messages per pedal press). After the notes have been set to "drone", it's then possible to modulate each note independently with TBMS poly-AT without sending further note ON/OFF messages.