Why would they need the extra nudge of Maithanet showing them a skin spy in their midst? So that makes me think the whole thing was part of Moe's failed plan to take control of the Three Seas himself.
To be fair, if Moe and the Fanim won, the Mandate would basically need to capitulate to him instead. He's still an Anasurimbor.
Revealing Simas was just to ease that transition, but not all all necessary for his plans, regardless of the outcome. Why not teach the skin-spy sorcery himself and make it into some ultra-uber-meta-psukhe-gnositic-diamos wizard that he could wield to destroy the world, rather than sending it off to some dusty library to rot and then out it himself?
A tool of such fast importance and power would not be so easily disposed for no perceptible gain.
And, by the same arguments those of you posted above, if he did it once, why not do it a million times? Make a whole army, hell a whole nation, THE WORLD EVEN, of skin-spy Psukhari absolutely dominated by him and preciously attuned to his will? They would be unconquerable, and he wouldn't need to send for his son off in Ishual to muck up his plans, or waste his time with silly Maithanet and his tenuous grasp on the Thousand Temples.
This is why the Meta-Moenghus argument is ridiculous. The Psukhe ruins the plot of the books if its allowed to continue. Having Moe be a master of the psukhe AND the tekne... C'mon. He only had 30 years wallowing in the basement of some old mansion with bad plumbing.