Guild Wars 2

Nothing, you keep playing with all the existing classes.

I’m pretty sure anet will send assassins with shadow form to raid your house so they can force you to buy HoT. If not. You won’t be able to do HoT content. But i think you’ll be able to use the new traits and also enter guild halls.

You’ll be able to play the game as normal. You will get access to the new core specs starting next week. You will also be able to play the new WvW map and the new Stronghold mode. You can also be invited to a guildhall.

With them giving the base game for free to new players they can exclusively develop S3 for HoT. This means that unless you have HoT you won’t get S3 for free. nor will you be able to purchase it from the gemstore.