I like the idea of sin bins in football too, bu they will only really work if you introduce a stop/start clock which only ticks down when there is actual play taking place. In rugby play can continue when players are getting treatment or else the ref can stop the clock if there is a big hold up.
In football this isn't the case so if a team went down to 10 players then it would often result in the short-sided team spending the next 10 minutes play-acting for treatment, goalies taking ages to take a bye kick, throw-ins being left for the full back to slowly trot up and throw it in, substitutes taking an age to leave the pitch. Now the refs can and should deal with these frustrating time-wasting scenarios already, but they don't. I can see it resulting in more frustrations and aggravation for the fans and opponents who should be benefiting with a "power play".
I personally would like a 30 minutes of guaranteed play per half using the stop/start clock, but this is too big a change for many people and no doubt TV companies would use it to end up slipping in adverts during the half.
There is also a bigger incentive for players to try to get an opponent yellow carded so may result in more cheating and haranguing of refs.