Holy wall of text, that took a while to read. Now its time for my own wall of text lol
I have seen alot of these posts, and honestly maybe there is a small issue with the current system, namely how the system reacts when a player needs to flex to a role they are not comfortable on, or refuses to flex for the good of the team, skewing the competitiveness of a match. This happens because the matchmaker does not know what you play, only what your skill level is, and makes teams based on this alone. Hopefully some sort of role queue with role based SR in the future will help with this in the future, although even then there are still characters in each role with such wildly different skillsets that the matchmaker still wont be able to account for this (think Doomfist vs Widow, or Hammond vs Rein).
In terms of MMR being shown, yeah you could do that, although most of the time you would see that it is extremely close to your SR, unless you have just gone on a huge win or loss streak, or are a decayed GM - And in this case the system works fairly well to assure that players who do not play for a while do not lose some of their ability over the break, and gives large SR gains if they are still competeing at the level that their MMR expects them to.
In saying all this however, you may have hit some interesting points in all of this, but I absolutely cannot believe your reasoning for the changes. You are complaining that your matches are too fair?? That’s laughable. If the matchmaker already knows that one team is far superior to the other before it even begins, what was the point of that match exactly? The losing team just got crushed and is pissed off at the matchmaker, while the winning team just got a steamroll that feels too easy and is unrewarding. Never mind the fact that lopsided matches have literally no show on where a players skill actually lies. By creating balanced matches, the games are typically much more interesting for the players (which really is whats most important in a video game), and you can actually prove the matchmaker wrong by outpreforming whats expected from you. By doing this, you prove you can climb, and are rewarded with SR as a result. If you underpreform, then obviously dont deserve the SR you currently sit at. By creating 50-50 matches, the game is decided by the best players, and allows them to climb by outpreforming the other team. If you are on the lower end of the players, then you will be carried, and if you are so bad that your team cannot compensate for it, then you obviously deserve the loss of SR. It sucks for those that lose the match because of this, but it is equally likely to happen to either side because the matchmaker has made a match that on theory should be even. This is also why SR fluctuates like it does, and is completely natural. No change to the system will change this, all you can do is improve as a player so you can be the reason your team wins in more matches, increasing your own SR. And in the cases where it is not perfectly even, the matchmaker gives lower changes to SR if the match goes as expected, and higher changes if the underdogs win. Because clearly if the underdogs win, the ranking of the players are off and need to be changed more drastically. Also, these matches are not made of a bunch of diamonds and a bunch of golds, unless grouping throws off the matchmaker (which is a legitimate issue). They are made of similarly skilled players from the same rank, which are sorted into 2 teams to create the fairest possible match, allowing those who should be climbing to prove their skills. If you want to climb out of Gold for instance, then you should be the best player in all of your games in Gold, otherwise you clearly are ranked correctly.
A final note, albeit one that is a little off topic. You may be spending time improving your play, but can still stay in the same rank. This is because the ranking system is a spectrum of where all players fall, and amazingly everyone who plays this game is improving as they play it! Players now are a whole lot more skilled and knowledgeable than they were in S1. This means that to rank up, you need to improve at a faster rate than the average rate of the community as a whole, which takes effort to do