Personally I always wanted an Elder Scrolls, online. Not what we have now, Id scrap the classes, trials, battlegrounds, instanced zones, and terrible separate pve from pvp silliness.
Id also can mega servers, classic PvP and PvE servers are more than appropriate.
All the best features from Morrowind, Oblivion, and Skyrim would be in the game. To include their superior combat systems, current combat system isnt as good as the original, tab target/assist will always be inferior to free aim.
Id expand housing to be more like Asherons Call and ArcheAge, their housing systems were better.
Essentially, this would have been Elder Scrolls, online and any Elder Scrolls continuation would have been update compatible for better features.