Hello, Holinka was Lead PvP Designer in Legion (i only know him before, i know he was on MoP and WoD too) , maked a break on wow and come backed in Shadowland as Senior Game Designer.
Here was his answer :
he feared the lack of healer role and how to adapt a soloqueue systems in wow.
But as i explained here my opinion, role should not be feared if it work like in random battlegrounds where role is in majority in mirror :
