Isn't a plus symbol used to indicate that a certain troop is ready for upgrading?
Scion, while I understand the desirability of not being able to discern the experience level of enemy troops, I think retaining the same troop name across experience levels would only add to the tedium already present in managing one's army. Let's say you are preparing for a big battle where you are outnumbered; obviously you would want to have your best troops up front. Having to talk to each troop slot and actually remembering which one was more experienced would be quite annoying, especially in a large, diverse army.
Different names not only make the troop list more transparent, they also add to the immersion. One could argue that death messages are unrealistic, but I think they give you a good indication of how the battle is going. Under your system, if you see a message "Swadian Brother Footknight was killed by (...)", you have no way of saying whether it was a mere recruit or a seasoned veteran.
My second argument is subjective and debatable, but I think the first one would apply to all players.
Regards,
Xawery