*This is in reference to the show runners writers ect overall not just Julie*
Delena was made a thing partially because fans wanted it, partially because she was obsessed with Ian and/or Damon. Julie claims she had never wanted Klaroline to go anywhere and that the sex in the woods was supposed to end it once and for all, but shippers kept sending threats to everyone involved as well as boycotting and petitions to cancel, so she had to keep bringing it back in order to shut them up.
But overall storyline wise not really, closest it comes that i know of is; 1- Elijah was just supposed to be Klaus' soldier then die but he was so popular that they kept him made his brother and created the Original Family. 2- Klaus was supposed to have been killed by Damon but he was so popular they kept him and created the sireline so to never be able to kill him (for awhile anyways). 3- Joshua was not supposed to survive at the end of The Originals season 1 but people liked him so they kept him.