SSE removes Dragon and Vampire attacks on the 5 major cities (Markarth, Solitude, Whiterun, Riften and Windhelm). While researching the topic, I found that USSEP still lists fixes for them in the changelog (fixes were made in Oldrim times when the attacks still happened). I found the following mentions:
Spoiler:
Vampire attacks should no longer disrupt the completion of Tending the Flame (MS05) once you've brought the book back to Viarmo. (Bug #22884)
No One Escapes Cidhna Mine (MS02) has been added to the list of quest exemptions for vampire attacks in Markarth.
If a vampire attack on a city is being shut down due to an interfering quest, the attackers will be immediately disabled instead of waiting for the DeleteWhenAble code to clean them up.
Dragon attacks can be falsely registered in the 5 major hold capitols. (Bug #15629)
The fixes could probably be removed now. Though any fixes for dragons that relate to attacks on smaller cities like Dawnstar and villages like Riverwood are still required, but I did not find any mentioned in the changelog with Ctrl+F.