Repeated by who exactly? And where is it said he wants to consume all reality?
I do agree with him manipulating Sylvanas, I made a thread on how I believe he tricked her into believing she was going to the maw, so she had no other choice but to ally with the guy who wants to break the maw open. You know who else was repeatedly evil? Arthas and it was revealed that even the Lich King Arthas(not the real Arthas) actually had good intentions.
Sargeras' plans were to use the legion to wipe out all life and then remake the universe and only the very high ups of the Legion knew of this. It wasn't going to remain a burning hell forever like most believe. in 7.2 KJ is angry with Sargeras and based on what Sargeras says, it does imply that Sargeras doesn't treat him like a pawn.Sargeras definitely saw Kil'jaeden as a pawn, I have no idea why you think he would see Kil'jaeden as equal. He literally tricked him into servitude by showing visions of a glorious future for the Burning Crusade.
KJ goes on about the crusade, Sargeras replies "Our Crusade" will prevail. KJ angrily tells him that they've done things his way and it's failed and Sargeras again refers to it as "Our destiny" and only questions his resolve and KJ again replies with more anger. This isn't how it's usually done with a master and minion, Sargeras shows no anger at KJ, only "C'mon man, have faith!!!"
So yeah, I dont believe that Sargeras treated Archimonde and KJ as peons, especially because they knew of what the was to come after the universe was wiped clean.