And the polymod, and LFO , after touch mod wheel , and other routing options IMHO are ENOUGH , if not more than what most people can actually artistically create and design great sounds with.
It honestly depends on what your doing. I've done a lot of stuff on my REV2 I could have never done on P6. I'd argue there isn't a whole lot you can do on the P6 that you couldn't replicate on a REV2.
The P6 is surely more focused when it comes to bread and butter / vintage poly synth sounds and its strength is in that focus and ease of access to these kind of sounds. I'd recommend it if your looking for simpler and right beneath the surface kind of sounds (and I mean that in a good way.)
But the extra depth of the REV2 cannot be understated. If your the type of person who likes to experiment and try things without really knowing where you will end up, the REV2 is fantastic. I've had this for 3 months and I still wake up in the middle of the night with a new idea for a modulation. Sometimes it sounds good, sometimes it doesn't work out but the journey has been my favorite part.
I might have made more music if I got a p6, but I've enjoyed more of a meditative/in the moment kind of patching experience on my REV2 which was my main goal for getting into synthesis anyways. The REV2 is a wonderful synth to explore in this way (and it can handle the bread and butter stuff just fine too.)
I'll leave you with a awesome example of the power of deeper modulations on a p8. The Rev2 adds to this substantially with its effects and ability to modulate them. Not my video but a great one. He has a few other nice songs that feature the p8 and really show off its sound (which is different than the P6 but just as viable musically.)
And a few visuals I really enjoyed making on my REV2 through a spectrogram, which is a sort of visual representation of the frequencies (vertical) over time (horizontal). I've lost afternoons just making stuff like this by attaching LFOS to LFOS to LFOS to LFOS to modulations etc, just to shape the visual image created.
While certainly not part of my argument for the the REV2 in any kind of musical sense, its a quite literal depiction of the power of the REV2s modulations and their ability to shape sounds.
I hope you guys can enjoy these as much as I enjoyed making them. They certainly look better than they sounded but that was the point.