You don't mention if you finished all the bosses when you last played so if you did not then it would be worth a play (with all the added changes since release - like mountain caves and new mobs) to do that.

Beyond that many people take on some self imposed challenges to make new game starts a bit different. From no portal runs to no boss runs to perma death runs. Each adds a different challenge.

For instance in no boss runs you have to 'troll mine' for your first ore and then 'Stagbreaker/maul search' for iron and silver. Nothing like smacking the snow in the mountains looking for silver while at the same time letting every wolf in the area know you are there to be eaten.

And some people are starting games and getting themselves established while trying to keep their exploration to a minimum so when the new biomes drop they can play the same save.

Lots of options...