For some reason, in recent times Blizz have hyperfixated on the idea of seasonal content instead of content that can stand the test of time. So they'll engineer all these systems that are promptly abandoned for the next expansion, instead of doing what they did with mission tables and fine-tune the concept until it works well as an additional system. Islands were an attempt to fine-tune the Mists of Pandaria Scenario system, and I hope they continue to fine-tune the system further but it looks like they abandoned the system in favor of a Roguelike system for Shadowlands. Warfronts could be a promising system with some work and better design goals, but again, the system is getting abandoned as 'seasonal.' Azerite armor and Artifact weapons both function under the same endgame-advancement philosophy, and both render that endgame advancement pointless as it's all discarded with the gear reset, putting you back at 0.
Would be nice if Blizzard designed a new system and worked it into the endgame as a permanent system to be fine-tuned and tinkered with until gotten right, like the mission tables born from the overbloated Garrisons, the Mythic+ dungeon system born from Challenge Modes and the raid system born from Icecrown Citadel 10H/25H.