To answer the question, “which is better and why?” is probably impossible lol. It seems subjective based upon the tweaks to the classes to strenghten or weaken various weapon skills and traits anet regularly makes.
Certainly there are ways to favor either crit, condition, or power damage and yet it would still be impossible to ascertain which is best if that was all we took into consideration. Add to the confusion the fact we are affecting vitality and toughness and healing power in the process and one more simple fact, a dying ele is a not doing dps but is dead or healing. None of which answers your question.
I think most players feel trying to answer the question is pointless. The answer rather lies in how you like to play.
What I do know is that we have only two damage conditions. In group play, depending on the other players and their preferences, I do see bleeds stacked to the max intensity of 25 and I can’t stack anymore. Burns stack in duration and those are usually stacked too. If there is a thief around, vulnerability is stacked at 25 too. How the game establishes the preference on whose burn or bleed is used in what order is beyond me. Knowing that would help. becuase it looks to me like we can be stuck unable to use our condtions. All the other conditions we have fall broadly under crowd control. Although not all are technically so for purposes of boss immunity, they are all non-damage dealing skills. Imo, because of this, a condition ele often falls primarily into a support role, or CC role, and not really into a damage role at all in group play.
Our power and crit skills on the other hand will always count. Power sacrifices high burst damage for a lower sustained continuous damage.
As I started the conversation with though, the characters vitality and toughness make a big difference in how often damage skills can be used. If the character is vulnerable to condtions and stuns, again a big difference. In my definition a glass cannon for example, it is a cannon that can fire. My crit build has 17,000 health, decent crit chance, decent crit damage, 4 condition removals, and 3 stun breakers. The character too provides good party support. It’s a team game after all.
