SWTOR's Patch 3.1 Conflict of Rishi back in Feburary which added some hard mode flashpoints and started PvP season 4 and SWTOR's Patch 3.1 Rise of the Emperor: kicking off PvP season 5 and adding new content and quality of life improvements.
SWTOR's Patch 3 update adds the planet of Ziost, a level 60 planet with quests and new things for you to do. Ziost has a ton of content, including updated with new daily quests, new world boss, and it already has a ton of daily quests and other things:

1.Outfit designer
which make your character look the way you want it to look. You can save up to 16 outfits, but you only get one slot before you have to expand.
2. PvP Season 5 - Relics of Gree / Bounty Contract Week
May 12 to May 19th the Relics of Gree will return, you can start on Ilum and farm reputation through various quests to get some pretty pets and gear.
May 19th until May 26th is the Bounty Contract Week, you can spawns missions on the space map for you to tackle, rewarding achievements and loot. This is available for all players above level 15.

3. Random Changes
Taxi paths opened up for everyone, you don't have to walk from one area to the other. A lot of life skills cooldowns have been reduced.
Group finder for operations has been changed to allow 8 players, but rewards have been changed, 8 player story mode bosses drop just 4 basic commendations, 16 player story mode drops 4 basic commendations and 2 elite commendations.
4. Class Changes
Alot of skill been buffed or nerfed, in order to balance between the various professional.
If you haven't played SWTOR for a while, SWTOR's Patch 3.2Rise of the Emperor updates a lot of new contents. If you want to go back to SWTOR, now is the good time.