In no way shape or form should bolster or something like it be introduced to FPs or OPs. What would be the point of getting any gear be? Let me ask you this, what would be the point of me getting better gear be if the game just bumped me up along the way? I would not need to buy any gear as I could run around in the same outfit that was given to me when I create a character.
The fun in this game is the challenge of the gear progression. In my opinion if you don't want to run with a group that has someone geared in green or has someone that is x levels lower/higher than you, than don't. You have several options which include vote kick, leave the group, or better yet get a group together with friends/guildies or what have you, before queing. Personally I don't mind running with people in greens, adds more challenge to me as a healer
I have several 50's and I have even managed to level all the way simply doing FP's with two of them. Some FP's were a little challenging along the way, but as I earned my gear things got easier, until the next one was available to me.
Developers, please don't consider implementing this PVE bolster into the game.
Should something be done about the XP nerf? Ya i think so. A suggestion that I have would be is that if there is a spread of no greater than 4 or 5 levels in a FP, then no nerf. In this way you cant power level someone. In higher levels maybe make the spread 2 to 4 levels. After the spread, normal nerf rules apply. This way your still getting a decent amount of xp for each FP, but the content is still challenging.