I wish Xal’Rith and Nekarat had their keys flipped and same with the infernal machine names leading to the realm of fright and terror.
It makes no sense for the final realm to be called the realm of fright which features a shadow clone of Diablo herself/himself, the realm of fright should be the realm of terror, and realm of terror should be the realm of fright.
What’s the problem? I guess most players only run Ubers for the Altar and if needed for the season journey.
I’ve thought this before but it’s minor. Could have been a simple oversight at the time but luckily it doesn’t affect anything.
I’ve thought the same thing myself… for years.
In D1 and D2, Diablo was always referred to as “The Lord of Terror”. So, it seems like his Realm should be called the Realm of Terror, opened with the Infernal Machine of Terror.
But, then I thought, it’s Blizzard. They do everything “bass-ackwards”. 
Make it so number one.
It’s the job that’s never started
that takes the longest to finish.