Changes in the past year
The search function on the forums sucks badly. It’s not you.
As for the game changes…so much has changed, and I really mean a lot, that you’re probably better off reading patchnotes (or joining a Guild and talking to people).
There have been far too many changes to really make a comprehensive list. The biggest ones are:
An end to culling in the open world and WvW.
Introduction of the Account Wallet for various currencies.
Introduction of the Living Story which changes every two weeks.
Achievement points now provide rewards in the form of chests.
Scarlet invasions randomly happen randomly in a handful of zones (similar to zone wide invasions in Rift).
Dailies have changed so that you only need to do 5 out of a choice of a lot more (but you get an extra achievement point for each extra one you do).
Ascended weapons have been introduced
Guild missions have been introduced (there are several types).
There’s plenty more, too.
This page sums it up pretty well: https://www.guildwars2.com/en/the-game/releases/