Some unit obsoletion suggestions

[Alien Valkyrie]

There are some things that always bothered me about unit upgrades, so here's a little list:

• I think Archers should be upgradable to Legions, since you need Warrior Code for Iron Working and except for costs, Legions are better or equal in every category.
• Horsemen should be upgradable to Chariots, same reason as above
• But what bothers me a lot more, since it stays in endgame: Riflemen. In endgame, I always use either Marines (for offense), or Mechanical Infantries (for defense), so I suggest that one should be able to upgrade Riflemen to Marines.

That's be it for now, maybe I find some other stuff that would be cool.