I will not add my own ranking, because I am not able distinguish influence of my knowledge and skills from influence of trial mechanics and power.
However, I would like to point out, that vAA has DPS lock (no matter how low) and it made it more difficult then vHRA in my eyes.
PvP - Recruit.
PvE - Dragon food
RPG - A guy who thought, that he can defeat daedric prince, yet guards still chase him off when he accidentally touches some object during daily writs.
I would say difficulty will fluctuate a bit depending on the role you're playing as well as specific bosses may be easier. Also some trials may be harder to pug, despite being easier for coordinated groups / guild runs. Prime examples are vSO and vMoL, which don't really have high DPS checks but require some form of communication. Overall, here is my (subjective and biased) list from a DD/Tank and guild-run-focused point of view though:
Hardest to easiest:
vRG
vSS
vKA
vHoF
vMoL
vCR
vAS
vSO
vHRC
vAA
I haven't played vDSR so I didn't put it anywhere.
Lots of these choices were quite difficult as I could easily swap one or two of these trials. Maybe a categorization would be better, where you put all Hard / Medium / Easy trials in the same group. It would probably look like something like this:
Hard:
vRG
vSS
vKA
Medium:
vHoF
vMoL
vCR
vAS
Easy:
vSO
vHRC
vAA
This would be very different if we're also including +1/+2 and hardmodes
This is pretty accurate ⬆️ for anyone still curious I have clears on all and VDSR tops my list. Very mech heavy, first boss and final boss bubbles are group killers.