I don't think that solo/coop is as challenging as full MP, having spent several hours playing it myself. Lets face it, even on advanced the AI is still slower and more lamebrained compared to human players. Unlocks and level-ups may be appropriate in both versions but I believe it may be more fair to cap unlocks and level-ups earned in solo/coop applied to MP and that any further unlocks and level-ups earned in solo/coop apply only to solo/coop and any further unlocks and level-ups earned in MP would be applied to both. Face it, MP is more challenging and the rewards and level ups should reflect it because it takes more skill and luck to earn them.
