Been playing WOW again for about 6 months, got a Lock to level 100 in readyness for Legion, been keeping an eye on the DPS rankings and healing ranking for Legion 110 with Artifacts for Raiding.
Lock's Destruction seems to be the better consistent spec, and Affliction apparently has its moments, i started off as Afflcition when levelling and switched to Destruction recently, will probably go back to Afflcition as i prefer the style of their Artifact, but i may stay Destruction. Demonology is not great, i tried it and it does not suit my playstyle.
Also levelled a Paladin to 100 to give me an alternative playstyle, looking forward to getting an Ashbringer in Retri, i also read they arent bad dps wise for raids but bring little utility.
Made the obligatory DH, dont really like the playstyle, doubt i will play it in Legion even as an alt.
Currently levelling a Rogue, the Outlaw spec has some decent fun visuals, but Rogue as a class is far too twitchy for my liking, i prefer a range dps style.
I am told that Fire Mage is topping DPS charts in Legion and Arcane is not bad either, tempted to roll another Mage (I already have a 100 mage on another server).
a lot of the driving factor of what to play in Legion for me personally is the Artifacts, as its the only weapon you use for the entire expansion, its visuals and effects play a big part, Scythe for Affliction lock looks superb, and the Staff for Destruction has some good skins etc, tough choice
Tempted to also level a Druid to 100 also before Legion arrives, purely to give me the option of a healer, i can use my Paladin as a tank / DPS, and my Lock as pure dps
Another thing, if you got any lvl100's lying around poorly geared, do the invasions for the ilvl700 gear, its fairly quick to gear up.