If Pikeman stills upgrades to Rifleman(or Musketman),they would still carry over that bonus against mounted units . What was the consequence of that in Civ5 Vanilla? Most of the people would try to avoid using Cavalry as much as possible,because they just can't stand against Rifleman with promotion against mounted unit . And such thing is even worse to Lancers,because their role in combat is severely limited by Rifleman with bonus against mounted,they wouldn't fight so many Cavalry(because of the first reason) and because they would still have to be built from scratch . No wonder why so many people said that Lancers were the most useless unit in the game . Making Pikeman upgrades to Lancer is a elegant solution to all these problems . But what about the requirement of horses for Lancers that Pikeman don't have?Well,to upgrade Warriors to Swordsmen,you need Iron and don't see anyone complaining about it .