Ahriman
Tyrant
Ok, but my point is that this isn't really a feature. At least, if you don't get rifling, you'll be blocked from upgrading anything to infantry.I knew how you felt about the Rifle gap. I mentioned it to point out that the game (for better o worse) doesn't always advance in clean progressions.
There is a big difference between: warriors become useless without the iron strategic resource, vs pikemen become useless full stop.Warriors without iron become useless as well - that's why I'm careful as to how many I build. Something similar could be said about pikemen.
Still, in an ideal worlds, we would have Civ4 style upgrading, where you could upgrade to multiple different units. I hate that they got rid of this.
I would love to be able to upgrade warriors to swordsmen or pikes, to upgrade rifles into Infantry or AT guns or AA guns, to upgrade knights into cavalry or lancers, etc.
This is one of the few areas where I think the "dumbing down" complaints were reasonable. The only reason to force a single upgrade line was to make the UI slightly simpler.