Now before I start I want to say this is my opinion and some of my ideas will be based off of current theory.
So I want to start of by saying that adding a new machine out of the blue would be… Ultimately boring. The machine reveal of course would not but I think its introduction should be apart of the lore itself. Currently we don’t have all the lore pieces but something that fits In with maybe what the machines Lack.
Example. The Russians decide to finally help without thinking twice and make their own machines these are less advanced and are not neurologically connected to mercenary. Ulmer being the supercomputer easily gains control over them and manufactures them himself.
Another would be a map change and machine update. Imagine that the map changes to convey the Swedish army trying to take down a heavily guarded FOA base. Machines start to lose and then they release the ‘new ones’. Then as you could tell the Swedish military back off.
This would not only add to the visual story telling but also to content. A massacred farmland area with bomb craters and fallen tanks and the ad of a brand new machine.
What I’m trying to convey is something more interesting (like apocalypse machines) could be done for adding new machines.
Thankyou for reading feel free to ask or talk about this in the comments.