1,3. is already true. There is post-morten review, we do see red-cards being cancelled and players being suspended all the time.
4. It is like this already. FIFA rules says that "when in doubt, favor the offense".
5. There has been some national championships with 2 field referees, it didn't noticeably improve the quality of the calls. FIFA allows rule experimentation from time to time on national fields. We've seen "blue cards" (where players must be replaced by others) for instance, two referees, etc... sometimes those rules end up in the official set: referees telling how many extra minutes of play was one of those experiments.
6. They do. English is spoken among all referees in a world cup game, except when all referees share the same nationality.
7. There are recognizable hand signals for all calls, but not for all rationales which would be impossible.
8. I have no clue what you mean by this suggestion. Just wanted to point out that it includes "discretionary power to the referee" while rule 2 suggested that this is "anarchy".
9. What happened to rule 9? Well, I want to use this opportunity to make a point that your comment (as most of comments suggesting new rules) seems to be sincerely trying to create a better game. But this game is just not soccer.
10. Players are not allowed to return immediately and they do must wait for the referees approval.