Rock is a generic SNK prettyboy with a moveset that is a mish-mash of two actually good designs. Out of all the characters in that game he's the least interesting. Of course Tizoc made it over him because a goddamn King of Dinosaurs is more unique and interesting than a random bishie.
The main problem with XIII is that it had terrible neutral. Save a couple of characters like King and Saiki it was hop rushdown all day long.
Bad normals, few good meterless AAs, poor projectiles. Some characters like Mr.Karate were so braindead because of how hard it was to keep them away or escape once they got in.
Also the more I look at the sprites, the less I like them. They are higher resolution but the shading is not very good and the clothing so simple compared to older KOFs. The prototypes looked much better.
It was not a bad game, but it had a lot of questionable things in it.