It's completely possible to be the big boom style class while also being viable in an average exp group, and this is accomplished by one nuke per mob being a reasonable % of mob HP and also recoverable between pulls. If the group overpulls, wizard will likely have to dump their mana bar and med through the next couple mobs while the more sustained DPS continue chugging along. This is acceptable iff the damage done over time is on par with other classes filling group DPS role, because in the short term the wizard is capable of higher burst. Being capable of higher burst does not mean the wizard should fall short in the group DPS role - it is simply a stylistic change - and over long periods of time the numbers should roughly be equal. No one would complain if an archer and rogue do similar DPS, and no one would say it makes the game boring - both of those classes fill the same group role, and they have stylistic differences in how they fill that role, and people choose one or the other based on the stylistic difference (stealthy backstabs vs hard hitting sniper, with various utility differences). Instead of lots of small hits and moderate burst, like the rogue and archer have, the wizard should be high burst and not wasting mana on small hits, but the damage over time should be roughly equivalent so that they are all viable filling the DPS slot in an average exp group, and currently it is not (and has never been even since alpha).
The problems with wizard are historical - at first it was melee vs non-melee wizard direction that people argued over. When they got rid of melee wizard stylistic direction, it changed to prospective wizards arguing over big hits and med vs people who never wanted to med and wanted a more active play style so lots of small hits. The devs seem to have tried to thread this needle with volley when it was first added, but I think this was a mistake, because it did not solve the damage over time problems with wizard, and it muddied the stylistic difference between wizard and other DPS classes. The ONLY thing that matters between DPS classes is the style/aesthetic for how they deliver damage, because in the end, doing damage in short bursts or doing it consistently can be EQUIVALENT OVER TIME, its just small bursts with 2-3s delay, or large burst with 5-6 second delay, and whatever downtime is necessary to sustain that, but if you pick any arbitrary time window, whether that be 10 minutes or 5 hours, classes filling a DPS group role should be roughly equivalent, and it doesn't "homogenize" the game if DPS classes are all roughly equivalent because players pick different DPS classes for their damage style. Saying that burst should be less viable over time doesn't make any sense, since sustain <--> burst is a spectrum. Surely it would be nice to have some mobs that require more burst and some that require more sustain, so that the stylistic differences would FEEL more valuable, but in the end, it still averages out to damage/time window, and players pick a class because of the aesthetic.
My credentials are that I was one of the highest level wizards in alpha, and have been giving feedback on this exact problem since alpha, and it has never been addressed, instead the devs focused on trying to make all of the players with different stylistic opinions happy simultaneously in a single class and ignored the main problem with the class. I'm hoping that these issues are addressed when they do the balance pass, but they should just get rid of volley and commit to the arcane artillery direction otherwise these problems will continue. This would have been easier to balance if they had not tried to mix damage styles in a single class.
