Thanks for the ideas! We are actually making some changes to the expertise system and how bolster interacts with the players in an upcoming Game Update (more info on this Update coming VERY soon), and this seems like a reasonable place to reveal some details about it, so buckle up and hold on!
To give everyone a common base of knowledge, let me briefly discuss how bolster and expertise work on the live servers as of right now (Game Update 1.7). Expertise is pretty easy, it is a diminishing returns rating that increases the damage output against other players, gives damage reduction against other players, and increases healing on targets who are in PvP. As you get higher in value of expertise, you need more and more rating to achieve the same increase (hence, the diminishing returns). Expertise only comes on PvP items, but inside PvP expertise is designed to be better bang for your buck than normal "PvE" stats.
The bolster system looks at a player's level and makes an assumption of the stats a player at that level would have and increases them to a target level defined by the designers. Bolster totally ignores what the player ACTUALLY has for stats, it doesn't matter if you are naked or fully geared out, it will give you the same bonuses either way. Notably, bolster will *not* give any expertise stat in Game Update 1.7.
In a major upcoming Game Update, everything changes, woo! Expertise still touches the same 3 functions (damage out, damage in, and healing out), but is no longer is a diminished return value, you get the same increase in power for the same increase in expertise, regardless of going from 0 to 20 or 2000 to 2020. We've also cranked up just how much expertise enhances each of these functions, so having good expertise is more important than ever. Additionally, expertise is no longer a stat that will grow throughout a tier of items, all PvP gear will generate the same total of expertise (caveat: This statement only applies starting with the new gear in the new update. Previous PvP gear will not quite have the fully intended expertise totals).
The bigger change is in how we bolster and add stats to players to even out the playing field. Instead of focusing on player level, now the bolster system will take a look at each individual item on your character and use that as the baseline assumption of power for that item slot. We then bolster each slot up to what we feel is the "entry level" of PvP power, at which we think everyone can be happy playing without getting simply out geared to death. Effectively, we bolster players to something like what our recruit gear set tries to do now in 1.7, but with much better accuracy and effect. Additionally, the bolster system will now grant players expertise when it feels it is necessary, bringing our entry-level power gap even closer to the end-game PvP power.
All of this put together should make our Warzone matches much more about skill in this future game update, and less about people who simply aren't in the correct gear, while still giving our PvPers some better gear out there to strive for.
Thanks for listening!