I think the idea of these rivalries is pretty good, but the arcade mode really sucks, its like a few versus matches strung together, even the final boss is just a 3v1 versus match.
Going along with the idea of rivalries, I would love to see a story mode where your character is placed in levels based on the games of their rivals, e.g. sly is put in uncharted themed levels against uncharted enemies or sweet tooth is put in god of war themed levels with gow enemies. Maybe even the final boss could be a hard/level5/red difficulty of their rival.
The current mode is too uninventive and easy for most people's taste, I think we all deserve a real arcade mode. (hoping this could be patch/DLC/PSASBR2)
What do you think would make a good campaign mode?
title fight designs would work pretty well i agree, although dont forget the current stages already incorporate various game elements