"Story quests" refers to specific missions or tasks within a game or interactive experience that progress the overall storyline or plot. Full definition
If you have only completed a portion of the black spirit quest prior to this change you will now need to progress through the new main story quests in order. (dulfy.net)
So quite a bit for those still enjoying the single - player campaign, and of course you can presumably take your goodies online — although unfortunately there're no new story quests. (brutallegend.net)
There are a good set for completing main story quest line pieces but the rest of them take a lot of time to explore. (andymerrill.com)