Inovated Horizontal Gear
We know that GW2 has its horizontal progression in upgrading your account wide with masteries, legendary armory/gear - BiS gear you can use on all your characters that are proficient in it without it ever becoming obsolete.
How would you like it if they were to make it so there is still Base DPS/Armor cap but the gear becomes more interesting... Example:
-Granting gear set bonus or straight up new spell that can be used for a build on a specific character.
-Is required to fight a specific boss (Like in Vanilla WoW killing Onyxia to get Cloak that would protect you against shadow flame from another boss) - Used for either for a protection or offense to even be able to hurt the bastard.
A new Boss releases that is fully immune to your poison damage?
However there is an old Boss that drops an item that converts poison to bleed allowing you to damage said boss.
Do this all over the game and with expansions without ever increasing gear score and character level making everything always relevant.
This is just my rought visualization and ofc it can be conceptualized better figuring the positives and negatives but as general broad idea what do you think?