Changes at a glance that I think are important in no particular order:
New MSQ, dungeon, and trial
New Alliance Raid
Combination mount from getting all the previous extreme trial mounts from EW
New Island sanctuary stuff, including a new currency
New Unreal raid (Singularity Reactor)
All alliance raids now have causality and comedy tokens with the exception of the Crystal Tower series. Duty Roulette for Alliance raids also has increased rewards with the same exception.
Duty Roulette alliance raid now has minimum Ilvl requirements depending on your class lvl.
Changes at a glance that I think are important in no particular order: