Gearing up for player vs player is all about activity. You can get yourself a decent set of starter gear doing anything, even doing it badly, because honor is awarded win or lose. To get weapons and top gear you need to reach levels of activity, be it capping conquest points or reaching a certain amount of honor gained.
The two major differences between gearing for PvE and PvP are that 1) you can get some of the best PvP gear without being the best if you are willing to work hard enough whereas no matter how hard you work at PvE if you do not have luck on your side and additional good players around you, you can not get the best gear and 2) entering in meaningful PvP group content begins from the start of the game and can start at any level, be it character level, skill level, or gear level but entering meaningful PvE group content does not start until you are max level and already have a certain level of skill and gear.
What this all means is that PvP is more player friendly content. A level 17 winning a battleground is no different from a level 90 winning one. But that is not the point of the post, the point is, with the concept that PvP is more player friendly, could PvE ever adapt to the reward design the way it is for PvP which is part of the reason it is usually considered more inclusive content?
For this to happen one thing would need to change that people that PvE would never give up willingly. Bosses can no longer drop loot. No loot what so ever. No more free passes or lucky players or gearing up off specs because no one else needed something. If you want your gear, you need to buy it, earn it if you will, just like in PvP.
For that one reason alone this whole "what if" is truly fictional and will never happen in a million years. I can hear the tears flowing now just thinking about this being implemented in the game. People that love their free and easy loot from beating bosses will cry like babies. What would be worse then hearing a million or more babies cry all over the forums? It will never happen.
But that is why this is a what if post, what if it did happen.
You would earn your valor/conquest from completing daily content. You would get your justice/honor, just for participating in content, win or lose. Could you imagine getting 10 justice points after each wipe as a consolation prize for at least trying? That is what battle grounds do, they give the losing team the ability to gain honor even when losing so why not justice when you wipe. So if PvE is going to adopt the PvP model you need to reward people even if they do not win. You should also award some sort of justice just for killing the trash mobs as well because honor comes rolling in fast and often even if you are on the losing team so in PvE it should feel the same, a fast and steady flow of justice, win or lose, just as long as you participate.
The valor/conquest thing would be like the arenas and raiding being compared. Winning in arena gives you conquest, downing bosses in raids will give you valor. Simple enough right?
You would collect your points and buy your gear. Wouldn't that be something special?
You could also lock out certain things based on activity and while many cry about it that is the best way to handle progression in PvP, at least until someone else figures out a better way.
For instance, you will be able to cap your valor every week but there will only be a few pieces available to you. The tier pieces will have a lock out on them, something like, you must down 100 current raid bosses to buy these pieces. Something like you needed to have xxx arena rating to buy this. Or how about the, you need to have 7000 honor this season, but in PvE it would translate into you have needed to earn 7000 justice this raid patch to buy this piece.
Could you imagine if there were a PvE version of honorable kills? One where you get points based on the types of things you killed. I would love to see what my PvE honorable kills would like that. Perhaps that is something that would be interesting to see even outside of this what if... some day.
Seriously, think about it, what if PvE was completely like PvP for gearing up?
The only real down side I see would be the lack of high end enchanting materials because there would be no drops to disenchant. Perhaps PvE could still drop items, but the maximum they would drop would be the same item level as the crafted PvP gear. So both PvE and PvP have ways to go about getting basic starter stuff and there would still be stuff to disenchant for the better materials, and of course, greens would always be part of the game.
I don't know why, but I like the idea of "you must kill 25 bosses before you can buy this piece" but it would run into the same problem the reputation to buy gear did. No one minds doing it the first time, doing it over and over on every character you want to play would get frustrating.
Goes to show you, even in a what if scenario, things can still end up having their sucky side.