At this point, he's pretty much stark slavering buggo.
His plan with the Prometheans was to take several thousand (Ten? A hundred at most?) robot Prometheans and pit them against a Flood that has consumed the galaxy AND has the backing of Precursor relics, which can go all H.P. Lovecraft with reality. Not to mention that the Flood created a logic-virus that was corrupting ancilla left right and center (Yes, Offensive Bias was immune, but I doubt that's a permanent state of affairs. This IS the Flood we're talking about).

He's also convinced that the Mantle has to be seized by force, and in order to uphold the Mantle, all threats to the Forerunners have to be extinguished... even if this results in a barren galaxy.

Starchild's logic has gone viral. I'm beginning to fear that the Halo Array may be the only viable option left to us.