I have the head canon the Celestial rigged the whole trial, so the events for another legion invasion could kick again and with that invasion the murderhobo will arrive to Argus and finish the legion with Sargeras imprisioned. They always act very weird and I doubt Bwonsamdi is the only demi-god with a boss that is not titan related.
Or both, that is. But that invalidates your argument of saying "glorious" to N'Zoth alone. Because it'd say both to it and its domain. A domain wich she aims to rule in N'Zoths name according to her own deal.
I really think Azshara played her cards the better there. He still won a lot with the deal, but the fact a dying mortal arranged a deal with a scheming God, and you can argue who won more of it, to the point we can't even be sure yet if N'Zoths plan includes murderhobos getting rid of Azshara so nobody can cast any sort of shade to its rule, kinda speaks to itself.