It is a horrendous concept. Petitions is going to multiply by a significant factor.
Named lockout by AFK groups
Warping to steal named
General asshattery around named
Selling named credit
Lag yay we love that
Since this also influences raids there is a motive to keep named locked out.
Then after a while its going to become avoid this expansion since the debuff is a pita. And here is the kicker the combat engine now has to cater for this debuff/buff, not like they have an already overloaded combat engine and have being reducing proc's for the last 2 years.. right ? Oh forgot to mention if this doesn't go to song window have fun managing your 42 slots of buffs that you may have one of them probably saying bye bye with this nonsense (yes lots of people have 42 buffs running, especially during burns)
15 minutes is rather significant but to your question topend is usually nec/mage/rog,rng (if humanoids)
/mnk/ber (not that many play anymore), the 6% difference just skews it into the caster direction once again. So "melee sucks to be you" is the message.
What I expect to happen, beta it is implemented but nobody can activate it since need named hunting.
Dec Live playersl love it and expansion raids is even more of a joke
Jan/Feb Devs realize its a huge mistake but meh vacation
March/April first nerf lowering damage or making it a pita to use or npc not casting the debuff for "reasons"
July+ It gets nerfed into the ground that it is not even worth clicking the button
PS: during LS I lost my named credits had to go redo 2 zones, nobody could explain what happened and it is not possible for CS to give credit.