Im a bit late on a reply but...
Damage wise, Nightblade (Pure Finesse) is going to put out the most damage. You can 2 shot trolls with non crafted gear on very hard under certain circumstances. That simply isnt happening with a magic build. Siding with Hierophant, and farming Gham Bleur for unique items, you can get a whopping 34% (1 in 3 chance) to evade, and with Nightblade you get a 300% crit hit every time you evade.
The bow, when maxed out is basically a shot gun. I run Lunalas Sight for the crit options. With the new level cap of 50, you can put 109 points in finesse and still have 44 points to divide into other trees. I go into Might for relentless assault with vengeance, and concussive force. Vengeance + Bulwark gives a 30% chance to reflect blows. That added with evade basically makes you untouchable. Bleed + Posion weakens whatever your attacking, giving you even more damage.
Shadow Caster (Finesse/Sorcery) comes in at a very close 2nd. You can use the exact same armor as you do with a nightblade, and if you build high crit chance, your mana will never run out. The mana drain perk is quite annoyingly loud though. With this setup you get bleed, and poison, for tanky enemies, and all elements to deal high AOE damage for groups. It just works for every situation. If Nightblade didn't have the evade perk, traps, and flare, Shadow caster would hands down be the best due to thier ability to handle anything.
I place pure Sorcery in 3rd place, as while it has high damage potential, it struggles against high defense targets like trolls. Sure, you can stun them repeatedly with storm bolt, but you still have to whittle down their health. Stacking elemental damage, even with meteor is still going to take a bit to kill a troll, or other tanky on very hard. They're also very limited in abilities. Sure, they all hit hard, but there's 0 variety. Get in range and nuke with meteor. If that doesn't 1 shot everthing, run up and use tempest. Fight over.
Faer Gorta summon is arguably useless, the heal ability is trash as well due to consuming far too much mana. Elemental rage is kind if just there, as guard+staff pull enemies together much faster. Meteor is of course the nuke, and if it was useful against stronger enemies, Sorcery would place higher. Another weakness is the amount of magic resistant enemies. That can be a problem without the crit chance and bleed+poison of shadow caster.
Pure Might is fun if you like big weapons and heavy armor, but ultimately utterly useless. That's not saying I don't enjoy it, but it simply can't compare to the damage of Sorcery Or Finesse as it gets neither elemental, or poison or bleed damage. Quake is useless. Wrath and Harpoon are far too mana hungry. Adrenaline Surge and Warlord are even more useless, as by end game, no one is getting close to dying (accept sorcerers). Battle Frenzy is ok, but enemies don't usually group up enough for the stacks to make much difference. Relentless Assault + War cry + concussive force are pretty much mandatory if you want put out any damage as pure Might. The cons simply don't outweigh the pros when it comes down to it.
You're much better off going with Might + Finesse, that way you can get weakening abilities and medium armor. I'll give an honorable mention to Might/Sorcery since with the warsworn set, you can reach 100% elemental and physical resistance. Though it's damage is arguably the worst.
Universalist is last place. Sure, weapon masteries are nice but the skill boosts are useless due to trainers and skill books. It has less damage than the pure classes, and barely gets up to middle tier abilities. You can't max bow, you can't get tempest, or war cry... the best middle abilities you'll get are blade honing, enduring agony and relentless assault. It's an OK destiny as you can switch to whatever you want, whenever. But you can do the same with a fate weaver, so ultimately it's the worst destiny imo.