1. BRING THE GAME TO STEAM. doing this will without a doubt breathe so much new life into the game. possibly even revitalize it like Rainbow Six Siege did. We might ask for new features, however that will not bring as many new people into the game that steam would do. it's as simple as that.
2. A Classic Covie Leader. Have a Prophet of Regret or something as a leader who has the old Covenant aesthetic. E.g, the HW1 base with the teleporter pad, classic Scarab, Wraith, Banshee design etc (unlikely due to needing to create new assets but still would be really cool.
3. MORE Custom options. I saw this earlier and I want to repeat it from more exposure. Allow us to set specific settings for matches such as only being able to use air/ground/infantry units, Ultimate Units etc.
I know this is more than three, but the more the merrier
4. More colouring options for our armies. An easy to do (I think) change that would allow us to maybe set our own colour for our armies or, add more colours to the Red and Blue side and let us choose from a list of them pre-match.
5. AI Bases on every map. This will bring the game to work almost like HW1 with how matches played out. it would also allow for expanding to not be so easy, as well as incentivise more Hero play as they'll be used to take out these bases as well as gain veterancy a the same time. This could be easily done using the current Flood assets to make these bases.
6. 2v2v2 or a Free For All. Nothing more to say with that. it's self-exploratory
7. Classic Maps remastered or a new Map, OR a simple Forging feature to make maps. I know how much resources are required to make the forge idea, however out of the options this would be preferable. This would allow us to make the Classic Maps and also keep pumping new life into the game well after you guys are done with it.
Out of all these ideas I've spit-balled, the most important would be bringing the game to steam. HW1 is there is it not? why not HW2?. Plus, getting the game on steam might even bump up the player count/revenue that we could possibly get a season 2 for the game.