Im really surprised all these years this hasnt been looked at. Ive played comp for close to damn near a decade now and have never finished a round. People get busy especially with jobs and life and dont remember to play mafia games for damn near two weeks straight without fail.
Im not saying that you should be able to play an entire round in one day but I think 20 hearts or something would be far more reasonable. Or do a scaling system where you can have all your hearts but as it gets toward the end there is decay.... this makes sense anyway as the people who are near the end of the round will have the most incentive and be sure to play so they can trophy, and the people who are out dont really care anymore.