For Halo Wars 2 I thought that a good idea would be is that when there is a battle there is a small cutscene where there is a command room ( lots of people walking around, space vie) and it shows a commander step toward a holographic table with a map, you choose your invasion plan by choosing the weapon the soldiers have ( this would be separated into groups like you can select what weapons a assault trooper would have etc. but you have to unlock the weapons)
you can choose how many troops will be sent out if there are tanks sending out longswords etc.
Then you have the option to go into battle. if you select yes then you are put in the shoes of a soldier ( if you have unlocked a ODST you can play as an odst etc) and you capture command posts around the battlefield ( much like battlefront) and then once they are all taken ( it takes a long time to get from post to post) or you can hold up and just wipe out the enemy.
what do you guys think?