I have another suggestion to Ubisoft in regards to the game, if they update the Modify Gladiator option to include more than just Delete Gladiator (as I suggested already)... they should add an additional option that opens up on your gladiator when he reaches a certain amount of wins. This option would allow you to upgrade your Gladiator to the next lvl above him (EG. if you have a white gladiator who has won 50 fights, he will have the option to upgrade to green). This way if you become attached to a gladiator and don't want to get rid of him, you could upgrade them to whatever price it cost for that color lvl of a gladiator.
White = Green for 2,020 silver
Green = Blue for 5,780 silver
Blue = Purple for 8 gold (if your below LVL 21) or 12,400 (if your above LVL 21)
Purple = Gold for 13 gold (if your at LVL 21) or 11 gold (if your above LVL 31)
And you could keep upgrading your gladiator with every 50 fights he wins, so you could start off with a white or green gladiator you might like and you could eventually upgrade him to Legend status... which would be pretty realistic. I mean, think about Spartacus and Crixus... they both started out as rookies in the show (which would make them either white or green in the game) and they eventually improved and became Legends. :)