I'm pretty sure they mention Deathsaurus being publicly executed some time in the past under his less cumbersome Japanese name Deszarus. I think it was when they were mentioning public execution being an option for Megatron in mtmte, referencing him and another.....

 

On the flipside, so many big Deceptivillains means there's not a lot of story need for more. So if we do get the rest, I bet it'll be not for some time.

Hm, if I did Deathsaurus or one of those others, I'd have him a 'middle war' leader. I.e. someone who arose during the war, was a big name for some time, but didn't make it to the end.

Well, no need for them to be perfect and boring, spicing up is still fine, just on the hero side  

Those are fun one...

Hm, maybe leaders of one of the distant colonies?