Probably beneficial changes:
• Referees will now be able to show team officials yellow and red cards for poor sideline behavior. Currently there is a three-stage verbal warning process that many coaches and referees alike do not fully understand. The clear use of cards rids the process of all ambiguity. FIFA still recommends a verbal warning before showing the first yellow for less serious offenses - for example: "minor/low level disagreement (by word or action) with a decision." A yellow card for a second transgression should, in most situations, prompt a coach to calm down and modify their behavior.
This rule change will particularly benefit young and inexperienced referees who are frequently intimidated by seasoned and obstreperous coaches. Also, if the team official can not be identified, then the head coach takes the punishment. This is useful because teams often delegate an assistant coach to harangue the referee while the head coach maintains an air of child-like innocence.
Further reading: How referees need to deal with dissent from coaches by Randy Vogt
• Goal kicks, and free kicks taken in the defending team's penalty area, are in play as soon as the ball is played and moves. The current rule, whereby the ball has to leave the penalty area before it's in play, makes no sense, especially as infringements just mean a re-take. This will improve the flow of play and stop teams who are defending a narrow lead from wasting time by deliberately flaunting the law and then forcing a re-take. Attacking players must still be outside the penalty area when the kick is taken.
• Substitutes must leave the field of play at the nearest point to the boundary line. This is to stop that aggravating waste of time near the end of a game when a foot-dragging substituted player trots in first gear from the field, pausing to shake hands most sportingly with anyone who might happen to be in their path and to acknowledge the applause of their adoring fans. The new rule is a direct consequence of years of unsporting behavior. If players are really concerned about their security (through having to walk around the field's boundary in front of opposing fans, say), then they can always make a direct sprint for the bench instead.
• Drop balls no longer contested. I once stood too close to a ball I dropped to two opposing young players and got the ball straight back smack in the face for my troubles - during a cup final in front of a couple of hundred spectators (try maintaining your dignity with a numb, reddened face, streaming eyes and momentarily dizzy vision). So I thoroughly welcome this change for drop-balls to be given straight to the goalkeeper (if play was stopped in the penalty area) or back to the team that had possession when play was stopped. Although in truth, this has almost become the norm over the past couple of years.
The jury's still out:
• No more "deliberate handball," everything is now a "handball offense." For the amateur ref, the advent of the VAR means that on weekends there are even more screams of "Handball!" every single time the ball hits a player's upper body. FIFA's new definition is less than helpful thanks to its ambiguous use of the words "usually" and "unnatural" in defining when a handball offense has been committed - for example (from the new Law 12): "It is usually an offense if a player: touches the ball with their hand/arm when: the hand/arm has made their body unnaturally bigger." What does "usually" cover? Who on earth can define "unnatural"? This change will mean only more delays and debates, and more players, coaches and spectators making usually loud not to mention unnatural appeals.
It is an improvement that goals scored with the hand or arm or right after a hand/arm play -- even unintentionally -- will be disallowed. That this also applies if the hand/arm play "creates a goal-scoring opportunity" will, however, again be tough on amateur refs. How far back in play will that be valid? Easy if you have a VAR, but at the amateur level be ready for players to start moaning about an alleged handball you let go a full minute before a goal was scored.
• The goalkeeper must have one foot on or above the line at penalty kicks. The current rule is both feet, but no one takes much notice of that unless there's a really blatant violation (that is, the goalkeeper rushes forward two or three yards before the kick's been taken). This law change supposedly allows goalkeepers some leeway to move in one direction or the other, especially if the penalty-taker is indulging in the fashionable 'stutter kick.' Although keepers will probably continue to move both feet off the line before the kick's taken, as they have been doing for years with impunity.
• Drop ball if the ball hits the referee ... and then a promising attack occurs, a goal is scored, or there is a change of possession. I can see the point of this to some extent -- FIFA justifies it by saying that it is "unfair" if one team gains an advantage from the ball accidentally hitting the ref. On the other hand, the referee has always been a part of the field of play, and players have to take that into account when they play the ball. I cannot say I've ever seen a situation where a player's tried to use the referee to make a wall pass and gain an unfair advantage. Nonetheless, this change may take the heat out of the odd controversy.
• Attacking players must be at least one yard from a defensive wall. Again, the intention is good -- this disruption became the tactical norm a few years back and is certainly irritating and often inflammatory. It may be difficult to implement if attacking players still insist on trying cause a 'disturbance' close to the wall (and one yard is a tough distance to measure), but hopefully it will just mean they stay away from the wall altogether, and then free-kicks will look like they used to.
(Ian Plenderleith's blog Referee Tales is a game-by-game chronicle of officiating in Germany's amateur and youth leagues.)