So Wrathion and Illidan are titans now? Lmao. You are suggesting things because you are claiming there are multiple views. How can that be the case if you are also not suggesting something? The audio drama "A Thousand Years of War" also implies the Titans knew about Argus as buildings and architecture was built similar to those on Azeroth. While it is possible that Sargeras had those built the more likely conclusion is that Argus was visited and ordered by the Titans.
So then your original point is wrong because you said you thought Azeroth was the last planet when you just stated Elunaria exists as a planet. Strange isn't that? The Burning Legion wouldn't have deprived anima from the Shadowlands because life still exists elsewhere and not all souls killed by the Demons are used to power Fel magic/machines. You also said Sargeras wouldn't have cared about other places with life so they can surely provide plenty of anima to the shadowlands, right?And we know there are worlds outside Legion control (Elunaria), life outside planets (remnants of Ka'resh).