I never said, sneaking is intended to be impossible in combats. I just said, I would wish it to be or at least be much harder, because it is just ridiculous. Not on good ridiculous way as the sneaking animation itself.
Also I would think, those 'sneaking' skills are mainly planed for guerilla tactics, thinning the herd with a surprise attack. Otherwise they are pretty overpowered (for example snipe)?
Synergist: I'm not even sure, if elemental ranger is any good, but a lightning spell that makes suddenly fire as well sounds strange. Only think that would make some kind of sense would be if every water attack would also do some lightning damage and possible stun chance. But on the other hand, there is hardly any pure water attacks, most water attacks are ice, so lightning does not make sense at all anymore.
A Touch of Frost: 3-5% chance seems pretty low and most non fire attacks do stun or freeze anyway I think, at least magical. Earth attacks normally get chained with fire, so frozen does not help anyway. The skill sounds like the old Ice King from DOS1, not sure how high chances were there.
Conviction sounds interesting, but perhaps more something like Passion as a name? But could be a bit strong. Perhaps if you are warm or burning shorter coulddown, if you are wet, chilled or frozen longer cooldowns. Guess would make Demon more interesting.
Fully charge: If you get hit by lightning attacks, most of the time, you would get stunned, if your magic armor is gone. So the extra AP would just be lost. And even when you don't get stunned, I'm not sure, it would be likely enough to get hit often enough with air attack to be worth. Perhaps if the skill would make you drain all electicity out of surfaces, 'suffering' damage doing so, but offering stun immunity? Living lightning rod?
Made of Stone: I think it would make playing with 'What a rush' less risky, if you could combine those two. So not sure, if that is good or bad. Probably good, not sure how many would pick 'What a rush' at the moment.