I feel that a summary would be the most interesting option. Seeing the perk progress on screen would take more space on an already somewhat cluttered HUD, or just be too much like Team Fortress 2 for my tastes. It'd be nice to see a bunch of random information about your performance that round, beyond perks and kill related stuff, to get an idea for how you play.
EG, in the GTA series, they track all kinds of stuff. How far you've swam, biked, walked, drove, how many kilograms of explosives you've used, how many bullets you've shot, etcetera. All kinds of really pointless information that's just neat to know. Seeing some of that mixed in with more relevant information ( the damage you've done this round, headshots, etc. ) would at the very least be something different to look at on the loading screen or somewhere similar.