It would be nice if no two characters in a party could have the same name. Identical naming is particularly annoying in mp when trying to use the battle log to determine the origin of a card or effect after it's been played. My suggestion is to add a (#) to the end of any identical names while in a game. For example, let's say I have 3 Human Warriors, all named Charles Bronson. Under this system, they would be seen in a battle as: Charles Bronson (1) Charles Bronson (2) Charles Bronson (3)
I concur. It's a cheap trick to name all characters identical, even if it only confuses your opponent once or twice.
Extending this to SP/custom as well: a battle can't have more than 5 groups on each side, and you can't have more than 100 chars in a group, so you can uniquely ID any char on the board with only 3 digits (and you only need 1 digit to ID a group).