I'm a huge Starcraft lore nerd. I also helped the Protoss, that makes sense from neutral point of view. As for Tosh and Nova, it even more funny when you learn later on from a different conversation about that one.
As for storytelling itself, they are pretty minimum, they didn't included many stuff outside of the main focus
If you finished WoL go try HotS story mode, HotS is like twice as much fun with better missions/more variety