Our current plan to address these concerns should become available in the Shadowlands Beta over the next couple of weeks.
First, we’re shifting the stat distributions on Conquest gear to always include Versatility. There should be two out of the three combinations (Versatility/Haste, Versatility/Mastery, Versatility/Crit) available for every slot. Secondly, we are adding a 2-piece set bonus, activated by equipping two PvP trinkets, such as crowd-control break (Medallion) or throughput (Battlemaster’s, Dominance, etc.) trinkets. This bonus will increase the damage and healing benefit of Versatility (but not the defensive benefit) while in Arenas, Battlegrounds, or War Mode.
The Conquest vendor will not offer perfect coverage of every stat combination, but neither does any other single source of gear in WoW. A player who favors Haste and Mastery cannot get a full set of Haste/Mastery gear from raiding alone, so if you’re someone who wants to be absolutely optimal, you’ll benefit from branching out across multiple types of content. Nonetheless, the result of these changes should be that a majority of the best gear for PvP now comes through the PvP system.
We look forward to your feedback on this, especially following your experiences testing the new itemization over the coming weeks.