They might could raise the voltage. I think the issue is the wire size going to the head (don't ask how I know this).
So while the voltage perhaps could be increased, the amps and watts would have to remain constant, which would not improve the power of the
device. I suspect that is the heart of the issue behind wanting the limit raised.
I suspect the next generation of eVic will have limits like the ProVari, which for most vapors is not restrictive. Something like 6V, 3.5 amps, 15 watts. It will improve an already good
device. I am a ProVari fan, but I applaud
joyetech for this PV. It is an innovative and dynamic device. May they continue to improve it.
All of the above is speculation on my part. Although I have seen the wires and am pretty confident that is the issue with the eVic power limitations.