This is more of a question topic than a suggestion...
Why hasn't ZOS put in some sort of end-game advancement mechanic in the game?
What I mean is... Why don't we have some way of improving our gear rather than just getting more set drops by completing veteran trials. Something that will make us feel more powerful and accomplished in the end. Something that will keep the content alive and active and motivating. Like... Why isn't there any kind of a drop or item or NPC (basically anything), that rewards successful highly skilled raiders or PvP participants.
For example: If you complete vMoL, you get a drop, let's say an orb, that puts special extra stats (anything from attributes, recovery, attack speed to weapon damage) or even just improves the quality of your gear (traits, enchants, armor) past legendary status and is
ONLY ACTIVE in PvE content to avoid PvP imbalances? This is in fact possible, just look at bonuses of Vicious Ophidian set as an example:
"(3 items) Gain Minor Slayer at all times, increasing your damage
done to Dungeon and Trial Monsters by 5%."
Since we have all kinds of different sets and builds and the motto is pretty much
"Play how you want", getting improvements for your character and build i this way would be perfect and motivate people to actually push content if they wish to do so and REWARD THEM without limiting or affecting PvP in any way whatsoever.
Actually the same thing could be done with PvP, let's say you would get to spend your AP on not just special PvP gear, but also some sort of special item that would function similarly as what I mentioned above, but in PvP. Let's say we'd have an item called "Cheesy Orb of Victory" costing AP and a new currency item from capturing Keeps and Resources.
This orb adds extra Weapon Damage to your weapon (let's say a 100) and this bonus only activates in Cyrodiil/Battlegrounds. <- This is just an example. It could be something totally different and for armor as well. Please keep this in mind.
Why hasn't there ever been anything like this?
This avoids:
1) PvP and PvE imbalances
2) Adjustments to CP, and changes to item level.
3) High skill requirement in PVP - which produces the most "hate" on the forums.
Honestly, if you spend a ton of time in PvP you should be rewarded for it. If you spend a ton of time in PvE and can do the hardest end-game content, you should be rewarded for it.
Every Trial could then provide us with different stats, depending on what kind of trial it is, so everyone doesn't end up doing the easiest trial over and over and over and getting strong no matter what would suit their class

All this of course would come with a cap, so players don't end up being TOO POWERFUL.
I avoided special rewards for TOP/GOOD PVP players on purpose, because this game is simply not being able to handle imbalances caused by it, therefore you'd only get it by spending time in Cyro/BGs. In PvE it doesn't stop you from doing anything, it only ends up being easier

and mobs sure don't complain that Player A hits them for more than player B.
Thanks for reading my wall of text. Like i mentioned at the start, this is more of a question/looking for opinions topic, rather than actual suggestion.
EDIT: Excuse any typos, this is sent from a phone.
EDIT2: Once again, since people seem to be misunderstanding me here... There would be
NO SKILL GAP BETWEEN PVP PLAYERS - ONLY TIME SPENT. I'm talking couple weeks here, not years and months. It would benefit players from completing objectives rather than just brawling. And It would be easily obtainable. The goal of the whole PvP part mentioned here would be to distinguish PvE from PvP even more and allow players to augment their gear and therefore THEIR PLAYSTYLE, even more.