I think that there should be a new group that is formed with 2 old one the forerunners and Jul madames convenient creating this alliance. I think having the brutes and the grunt and jackals (NO ELITES) should just join the forerunners having badass orange and black armor and the grunts with boltshots riding the Promethean Knight and even having. promethean equivalent to a Spartan or an Elite. So a Promethean Army/Covenant Army. Next, the banished again more of brutes and fewer elites the elites should join Swords of Sanghelios (It would be badass to see the arbiter and Atriox Fight!) Then the UNSC and The Flood as separate alliances. The UNSC Acconally alliancing with SOS. More Missions on Halo and Maybe making the evil Cortana a forerunner clone that works the Promethean Army/Covenant Army. They should make marines and ODST stronger and give them the spotlight. Also having New almost spartan like marine armor. I hope you guys agree! 
Feel free to use the wishlist threads.