Football and rugby are come from the same origin, so I think both kinds of game can learn from each other in terms of rules. Now football games are more intense than last 10 years, so I think football should adept and improve the rules in order to make it better. I think we should learn from rugby because some rugby rules are designed very well for the football game.
Sin bin: In rugby, the referee has the right to "sin bin" the player, that is, suspend the player for 10 minutes. When a rugby player receives a yellow card, that means "sin bin", he needs to be suspended for 10 minutes. If the remaining time is less than 10 minutes before halftime, the player will be suspended the remaining time in second half. If the remaining time is less than 10 minutes before fulltime, that means the team is shorthanded until the end of the match. Since football games are more intense and more personal fouls, sin bin can make the players calm down when he is suspended. More importantly, as the player knows the team will be suffered by his personal foul, he will be less reckless. For the fans, we can see more tactical moves for both teams in that 10 minutes as the shorthanded team will try to avoid goals and the other team try to score goals.
Blood bin: Blood bin in rugby means when the player is bleeding, or is injured, he will go out of the field to receive treatment. Unlike football, replacement is allowed and that replacement will not be counted to be the usual substitution. In other words, when the injured player has received the treatment and available to play again, he can come back to the field and the replacement player can be also available for the other substitution. Football players also get injured, no matter it is real or not, it takes lot of time, so blood bin can assure the game flow as well as avoiding the team to be shorthanded at the injury moment.
Video referee: There are lots of arguments since World Cup 1966, when England scored the controversial goal and won against West Germany in the final. I do agree with the video referee, but there is a condition. Similar as the rugby union (coz rugby league sometimes abuse the video referee), the referee should have a decision and the video referee is the assistant to the referee. The video referee can be implemented ONLY under the condition related to the goal, that is, ONLY the situation of the ball crossing the line or not, and the video referee shouldn't be used in the situation of deciding offsides. Video referee can confirm the ref's call, making the correct call otherwise, and to be inconclusive. If the video referee is inconclusive, the referee's decision is the final decision. It can avoid the goal line controversy.
Time offs: This is the most important. The mentioned 3 changes must be supported by time offs. The referee can stop the game clock under the situation of the player is injured, players lose control and starting a brawl, and the goal line controversies. For example, Chelsea's Petr Cech was collided with the Wigan player and made Cech concussed 2 seasons ago. The match had delayed for about 10 minutes and even the referee had 8 minutes injury time before halftime, it is still unfair to Chelsea I believe. Time offs can also the good solution to the time wasting. Players fake their injury in order to waste more time if the team is leading. I agree time wasting is a tactic, but I'm not asking for being fake. If the player is injured, stop the clock and take their time to receive the treatment. However, one thing is important is, the match will not have injury time. When rugby reach the end of the game, the referee will only allow the trailing team one last play for them to level the match, if they fail to do so, the match is over. Football can learn from this, only giving the trailing team one last play and make the match better in game flows and to be more fair.
Sometimes I agree to that quote - Football is a gentlemen's game played by ruffians and rugby is a ruffian's game played by gentlemen. I want the football game to be more fair then now, so I want some major rules change in order to make it happen.