Yeah, I'm down for some space cop shenanigans. Doubt they'll go full buddy cop movie on us, but having two (or three!) primary leads is a solid idea.
Idea: have Stewart as the new lantern, given the full origin story treatment. Hal's actually been a Lantern for a while now, but he hasn't been back to Earth since he got taken to Oa to take the oath. The reason why they're recruiting a new Lantern for Hal's sector is because it's becoming increasingly apparent that Earth is going to need some full-time attention, after Hal couldn't get there in time to deal with Zod.
EDIT: And hell yes to bringing back Mark Strong. Just straight up say "he was amazing, we're bringing him back, no, the old movie is still being abandoned."