OK, please permit me to correct you a bit on this part. The PvP chest can be construed in a way just as the m+ chest PLUS the island quest, and here is why. You consider that to get the pvp chest, you would need to make a continuous (weekly) commitment to pvp for a fairly long time, but unknown to most players that don’t really pvp, it isn’t so. This is what you actually need to do to get the highest reward you are capable of from it with the least amount of effort involved:
Step 1 - get to your highest rating you can reasonably get in one of the three brackets only - the one you do the best in. Let’s assume you are a 2400 level player, you will have to make an initial time investment to grind up your rating to 2400 when the season starts. You will do that anyway if you are a 2400 player, because you will want your title and mount.
Step 2 - Now that you are at 2400 in a single bracket, let’s say 3v3, make sure you have another bracket, preferably the RBG bracket, as low as possible. You can even join really bad teams on purpose and lose games on purpose, your goal is to have low mmr (matchmaking), to a point where the players you meet there are a joke compared to you in pvp (it wouldn’t be hard for that to happen if you are a 2400 player).
Step 3: every week, win one game in your high rated bracket (3v3, in our gladiator player’s case), and then go to the low bracket (RBG, in the same case) and win 1 game each day at 1200 mmr. Should be faceroll enough, similar to well geared pve players grinding out island expeditions.
All you need is 500 conquest points, and the daily RBG awards 150 (it has been buffed). Do it 3 days in a raw, and you are done (450 conquest from the 3 RBG wins, 50 from your one win in 3v3), you will receive the PvP chest based on your highest rating in a bracket where you won at least a single game (in your case, the 3v3), and your conquest cap can be filled up anywhere (1200 mmr rbg in this case).
While it is true that it is a littlebit more time intensive than the m+ chest, the difference between doing this as a pvp player and doing one m+10 and the island expedition weekly together as a pve player is practically 0. The initial time investment early in the season to grind your rating can be equated with the initial time investment made by pve players to learn the m+ dungeons in the first place. The only redeeming thing is that to actually reach 2400 or even 2100 in pvp, you would be part of a far more exclusive group of players already than to complete a m+10 in pve, there is actually a major difference there: m+10 is something attainable by a sizable group of players by their own means, and by anyone through legal boosting for gold, while 2400 rating cannot be bought and done in a legal way unless you are capable of playing at least around a 2k level on your own. 2400 rating also represents around the top 1.5% of arena players, and even 2100 (the duelist threshold, which awards 380 loot in the chest) represents between the top 3% and 5% of arena players at most, depending how long the season went on.
Allow me to also disabuse you of this notion, that this weekly pvp chest is some sort of love pvpers get: practically no committed pvp player likes the current system. What almost all want is to have the gear vendors back, to be able to grind out the currency and then get the items we want, at a steady, weekly progression, just as it was before Legion. I haven’t seen a single thread in the pvp forums here, on mmo-champion or on any forum whatsoever where a committed pvp player said “this system is good”.
I believe that what you propose could work well for mythic+, but not for pvp.