It's so sad that they dumbed down the game to that degree. Threat served a very important purpose, which was to tie the group members' performance together. Tank generates threat on main target to allow DPS on it and aoe threat on the rest to keep them off the healer, the DPS damage the mob as much as they can while staying under the threat ceiling, healers keep everyone alive without generating too much threat to get everything on them. It was a beautifully balanced system, and meant everyone had to actually care about what others in the group were doing instead of mindlessly spamming their own rotations. But of course it's too hard for the current generation of gamers, who cannot master such complexities as "DPS the tank's main target and don't over nuke".