Here's the issue with introducing rule variations... it just leads to a giant mess.
Look at professional pool as a case-study:
The World Pool-Billiard Association (WPA) has posted the "official" rules for various games on their website. However, various tournament organizers like/dislike certain rules, so they have a tournament and say, "well we're going to play 9-ball, but we don't like that you can 'luck in' the 9 so for our tournament you have to call the 9-ball." (For those who don't know, 9-ball is not a called-shot game. As long as you contact the lowest numbered ball on the table first, if the 9-ball falls, you win.)
Other tournaments don't like certain rules in 10-ball so they hold tournaments with their own rule variations.
Now when you go to any pool tournament, professional or amateur, you have absolutely no idea what rules you're playing by and everyone just gets more and more upset.
The Professional Pool world is a mess, in part because everyone takes it upon themselves to set up rules they think are better than the published standards.
Now let's address your arguments for why your changes would improve the game...
I just came back from playing 9-holes at my local club. I caught with with three braughs who were having a bromance love fest as they may their way around the course. They did not acknowlege my existence and did not let me play through. I usually don't mind waiting for people in front of me but... On a Par 3, they were on the green when one of them addressed the ball, then looked up and started to talking to his friend! I let them clear the green and drive to the next tee before I even approached my first shot. When I got to the next tee, they had just finished teeing off! I let them play that par 4 out entirely before teeing up my ball and I STILL caught up to them taking their second shots on the next hole. This was the 9th hole and they stopped on the fairway to buy something off the drink cart even though they were about to make the turn and drive past the clubhouse." I finished 9 and saw their carts still sitting at the 10th tee.
They were not playing slow because they were following the rules. They were playing slow because they were d-bags who didn't/couldn't acknowledge that other people were on the course.
The rules apply to everyone equally. Brunettes don't get one set of rules while single-digit handicaps get another. The rules apply to everyone equally therefore are already fair.
Easier To Understand:
Introducing variations automatically make things more complicated. "Are we playing standard USGA rules or MEFree variation?" "Uh.. MEfree, I guess, but what's the case when you hit it OB? Do I drop for a penalty or not?" "uh... I can't remember, we'll just drop and move on" This is what people already do, so why add to the complexity!?
In other words, by creating variations that you think improve the game, you have created "house rules 8-ball" which no one who is serious about pool cares about.