halocline
Contributor
Nitrox capatible (future proof)
Balanced (easy breathing)
Non-Piston (keep water out of the unit for longevity)
DVT (nice but not required)
A couple of quick things; balanced has very little to do with easy breathing (except at very low tank pressures), and "non-piston" has nothing to do with longevity. All regs are nitrox compatible; only O2 mixes higher than 40% need 02 cleaning.
That said, maybe the zeagle envoy or aqualung titan would fit your criteria.