The early game has a pretty large issue with lots of inactive time due to a lack of accessible content. You are pretty much just waiting for raids to popup and then you have a somewhat subpar battle. It would be really cool if there were more activities to do at the lower level, like increased raid popups or high threat raids which are built for high quantities of low rank units.
Another thing that would be cool are structures that could trigger or enhance raids. Something like a beacon that might get raider/critters to attack your base. It would also be a neat way to introduce low level boss strikes or get some early access to mid game materials like bars for early unit promotions.
Maybe this could also be building specific, like boosting a mine or a logging camp but there are strong raids which will attack the resource collector and until the raid is defeated the resource collector won't collect resources, so there is a high risk high reward way to boost early game speed.
Anything more than just waiting for new raids to appear and then being done with the game for an hour or more.
If you have any ideas those would be appreciated. I also like talking about why an idea is good or not rather than just being told it sucks so feedback is appreciated.