I don't care about medals, I want to see proper stats - and mine only, it should never be a competition.
I want to see hit percentage, headshot percentage (percentage of bullets that hit the head instead of some other body part), total damage dealt by weapon(s)/ melee/powers, number of each enemy type killed, total amount of shield/health damage taken, power-specific stats (e.g. total amount of shields restored by Geth Turret), total distance walked during the game, number of incapacitations, number of bleed outs, number of revives etc. All kinds of stuff like this. This would also enable all kinds of possibilities for interesting community challenges.