Mmmh indeed… Maybe some balance could be found. The HC is readily trainable, the rest requires a prior investment in my idea and have different stats. For the obsolescence, a creative solution could be having a one use ability to turn all HC into Arquebusiers. You would lose some value though.
This units could work in a Fast Imperial strategy though!
It’s kinda like the issue with grenadiers (even if slightly less extreme). There’s also the fact that having units stronger than hancannon would obsolete non-gunpowder units really hard, so they would need another upgrade. At that point you are halfway to the point of just making a new age after imperial.
I would say more but we’re going too off topic. Will have to wait.