If you are a really bad player then you could probobly pull equal numbers as fire compared to arcane cuz arcane is harder to play (IMO), or if you only do lfr (note the "OR" meaning the 2 does not nessisarly relate to eachother) fire is fine you will still outdps the afk players meaning you are among the ppl boosting rather then being boosted.
But if you are doing normal mode and you have a brain then you should really take the time to learn arcane, scorchweaving (go with ring of power imo since its easier to manage then evocation and imo preforms better on low movement fights).
I say fire is not viable simply because its an inferior spec, and as a dpser your job is to dps. playing fire is like a healer arguing that he can manage healing as ele/shadow/boomkin, ofcourse the difference is not so extreme as in these cases but the point being fire is inferior as a dps spec and you wont be doing your guild a favor by preforming less then you could. (and arguing that you still top meters as fire or still out dps most ppl isnt an excuse, you are still underpreforming, only not as much as the rest of your group). You should play arcane for the very same reason locks play mostly affli, hunters play bm/survival, warriors dps as fury or rogues play assasination.. because its lets the preform the best. because thats what the dps role is all about, doing their best to dps down the boss be4 healers or tank screw up/go oom.
And yes i know that some bossfights favor other specs, fire is probobly still best on stone guards and garalon and mby even some more fight, same goes for other classes on diffrent fights but if you look at the entire teir as a whole, arcane is the spec to go and there isnt rly any excuses for staying fire unless you find arcane to hard to play (wich actually is the case for alot of players, hence what i said in the beginning of my post, a really bad player will pull equal or even higher numbers as fire compared to arcane)
---------- Post added 2013-01-25 at 02:22 PM ----------
including all 10man logs will give us logs where players died and with some terribad players and undergeared alts, inferior rotations and alot of logs that doesnt have anything with competetnt play to do at all.
the reason to make a chart with only top logs whould be that you can be confident these players know the spec and play it smartly.