He's somewhere underneath Cybertron, converting it into a warship

 

On second thought, I just re-read The Death of OP, and there is heavy implication in Op's monologue that Megs would be on Cybertron, attempting to spoil the alliance. This would support some involvement with Metalhawk, but doesn't necessarily discount Megatron from having influence over Overlord's reconstruction.

 

RID and MTMTE covers by *PriscillaTR on deviantART

This is MTMTE and RID #7(and #8, possibly)'s RI cover, featuring Megatron.
Does that mean he will return? If so, on MTMTE? Or on RID?

 

Him and Galvatron will likely come back as Unicron's Herald's.

(wild guess)

 

The only thing I can think of that would be worse, is to be subjected to the further exploits of IDW Spike Witwicky.