The reason Bolster exists at 55 is so fresh lvl 55s can actually play a constructive part in a match until they have full 2018 gear. I know some PvPers think that new 55s should have to suffer through several days of being massacred over and over as some sort of sadistic initiation to PvP but if you do think that ask yourself this question, would you want those fresh 55s on your team? If you take Bolster away the first thing most players would do would be to inspect everyone else's gear in a WZ and a lot of them would probably quit if they found more than 1 player with less than 2018 gear.
The problem with bolster is not that it exists but that it is too mathematically complicated and can be easily exploited, PvE gear should never be better in a WZ than PvP gear, just as PvP gear should not be as viable in Operations as PvE.
I believe Bolster can be improved and made to work much better, but I also suspect that my solution (see bellow) would require a lot of reprogramming so I doubt it will happen.
Anyway my solution is as follows
1. Remove Expertise from PvP gear and replace it with an item flag that marks the gear as PvP
2. Choose a base line gear set for PvP, right now I'd say the old Partisan gear stats would be about right.
3. When a player enters PvP (either a WZ or in Open World) the bolster system checks each piece of gear (including individual mods, enhancements):
- If the gear has a PvP flag on it Bolster leaves it alone
- If the gear hasn't got a PvP flag and has lower stats than Partisan it is Bolstered up to Partisan
- If the gear has no PvP flag and has higher stats than Partisan it is "Bolstered" down to Partisan
4. Remove Bolster Up (but leave Bolster Down) from Ranked WZ, if you don't have at least full Conqueror you have no place in Ranked PvP.