Don't really know what instances you have experience from, but WD/S isn't burn DPS on any instance.... The longer fight the better, as after about 30s with proper buffed cent you should have constant 25% attack speed buff on. I do not mention centaur DPS, as beast can do about 2M DPS for first 30s and about 1,5M after, of course buffing that high would require some time, but it's possible and here add master DPS, that probably would be higher during burn phase (maybe besides belatis) and ok much lower after, but as everyone else (and you have 25% speed buff and wait only 60s for next burn and faster is only warrior`s berserk). Personally I usually have aggro issues on 2-nd belatis boss with 2x recon VII.
As for WD/W only burn and probably only tanking boss, so by adjusting stats to have more HP or it would be much weaker than WD/S (that's from my experience).
M/W on belatis doesn't exist. TOP DPSes will do at minimum 3x more DMG, probably more like 5-6x. The only bosses where you could use mage for his AoEs would be 3-rd and 4-th, but then he will die in seconds, so using too much AoEs is not an option. Simply time with lower mDef has finally over, showing weakness of mage and that W/M is no longer OP.
And do not get me wrong, all classes I mentioned before are really close and some have other adv over others than just DPS.