-There will be higher chance for you to get a lengendary(as the pool of different items will increase), but smaller chance for getting the legendary you want.
-You will reach the cap of max AK.
-You will probably max out your artifact weapon(and maybe work on other spec?).
-It will be much easier to reroll due to catch up with AK.
-You will probably have less stuff to do as you don't farm rep anymore. It will probably be weekly storyline or farming various stuff for quests in raids/dungeons(still more content combined all the expansions together).
-Flying.
What kind of direction do you expect in the nearest future?