Higher league players have not come across such hard matches against priest, this being possible throughout the additional, rarer class specific cards players have unlocked.
I have tested the possibilities of winning matches with lesser powerful cards and it was a complete success.
My proposition is very simple: basic cards for the priest cards to be rethought.
Cards such as Mind Vision, Mind Blast & Mind Control can be swapped with Auchenai Soulpriest, Silence & Temple Enforcer ( personally I also use Mass Dispel instead of Thoughsteal as well).
By doing so lower league players, both main priest user and non main priest users, can benefit from useful abilities and higher league players ( masters especially ) can continue as they have always done, no changes in their gameplay.
No nerfing of priest needed anymore as higher league players have not submitted many complaints, their decks being strong enough to stand against the priest, thus making it a fair and pleasant match.