Its the maps and mobs, if some mobs were made to counter rogues tank like armor stat it could help.

Hopefully the tanks get a large increase in hp for new weapons, and mobs cast armor debuffs on our party. Cutting armor values in half(through mob debuffs), while giving tanks op hp buffs, might help.

Also the armor on mobs should be higher, while increasing CC for the mage class.

So: Large hp boost for tanks. Mobs cast armor debuffs. Higher armor for mobs. Longer/more effective CC for mages.

Sts, your absolute best example you have to work with is the Mausoleum expansion. By far your best expansion is years i would say.

They could alternatively add a few skill tweaks. Class specific passives or the like. Raw damage for tanks, crit hit damage(not chance,damage) for mages and whatever crappy for rogs.

Just some thoughts from someone who doesnt play tank :-).