So you disagree that damage is a requirement to win in arena? So you'd take demo into 3s at 2.2k rating do 0 damage and tell me it's okay because the 5% for raiders doesn't matter? Bullshit.
Its QoL. If a pure DPS spec does bottom end dps. Does it go into arena? Does it raid? No. You bench it in both activities.
And it doesn't matter if its a small % or not. If blizzard suddenly went "you know what we don't care about PvP DPS' dealing damage the entire of arena is now based on healing and tanking damage" 100% sure any pure dps class would be up in arms about that.
If youcan't understand the basic lore of Warlocks and the thirst for ever greater power. Then it's pointless. The ultimate Demonologist power is having abilities akin to the demons you seek to become stronger than. Aka metamorphosising due to the power you contain. Now obviously the illidan model shouldn't be demo's. But that doesn't mean we can't have wings/horns and have it as a stance like boomkin form. I don't get people who can't grasp that. Or that it can be different than what it has just been. It doesnt have to be another set of skills. It can be a cosmetic/cooldown/whatever.