I apologize in advance for the length of this post. I have been a MLS fan since the beginning, and this was one of the dreariest seasons ever. I had to laugh at the forced "excitement" of "Decision Day." 12 out of 20 teams make the playoffs? How is that exciting? I realize that we Americans like our playoffs (I do to). But one of the beauties of leagues like the EPL is that the champion truly is the best team. There is a purity there that we all admire. However, without relegation/promotion (which I am not advocating) that wouldn't work in the US. So allow me to propose a compromise- a system that awards only winners, but still maintains the playoffs: 25 teams 5 divisions of 5 teams each 32 game regular season (play each division rival 3 times, every one else once) 6 team playoff seeded as follows: The five division winners seeded by points with the 2nd place team with the highest point total seeded 6th Round One (2 legs, total aggregate score): Seed 3 vs Seed 6; Seed 4 vs. Seed 5 Round Two (2 legs, total aggregate score): Seed 1 vs lowest remaining Round One Seed; Seed 2 vs. highest remaining Round One Seed Final: Single game at highest seeded team's stadium The idea is that the excitement of the playoff hunt should continue to the end of the season, the regular season becomes much more meaningful, and only true winners are rewarded. Just a thought.
This is where your argument runs off the rails. The Champion is truly the best team, if and only if 'best' is defined as 'getting the most points over a double-round robin where wins are rewarded three times as much as draws." And if that's the case, you're just begging the question: You're saying it's better to play a double-round robin to determine a champion because it's better to play a double-round robin to determine a champion. But, because you have no actual argument to back that up (you might, but you certainly didn't give one here), any other definition of 'best' is equally valid. Y'know what I think is dumb? Currently, Liverpool sit at 3rd on the table and City first because Liverpool only beat West Brom 2-1, but City beat Bournemouth 4-0. That's really dumb to me. West Brom and Bournemouth don't matter in the title race, so why should how badly they were beaten (let's remember, that both teams won) matter at all. Much more admirable is a team that demonstrates that they belong in the Title Picture, and then rises to the occasion against the best teams in the League. Something no EPL team ever has to do.
It may look nice to be in first during the season due to having easier games played earlier, but the end is what matters, and at that point everybody in the Premier League will have played the same schedule. It's also unlikely for goal differential to decide the title. Adding playoffs after the Premier League would require players to play more games (which is already a problem for Englihs clubs that go far in the FA Cup, EFL Cup, Champions League, and/or Europa League) or relegated more clubs to downsize to 18 clubs. If there was a 4 team playoff done in 2 leg Semifinals and a 1 game Final at Wembley like the promotion playoffs do, that would be up to 3 extra games. An 8 team playoff with 2 leg Quarterfinals before that would be up to 5 extra games. I think it would be strange if a club could play at Wembley in consecutive weekends, once for the FA Cup Final and once for a hypothetical Premier League Playoff Final. Without playoffs, a Premier League club could clinch the title or relegation weeks in advance, but would never have meaningless games at the end of the regular season followed by meaningful playoff games. By adding playoffs, Team X could rest players at the end of the regular season (to be more rested for the playoffs) after having clinched the 1 seed. That could help Team Y make the playoffs and Team Z miss the playoffs if Team Y was lucky enough to end the regular season against Team X.
Having more conferences/divisions doesn't change things. You're still reducing the size of the playoffs and creating a lot of meaningless games -- while bringing in the worst aspect of the NFL format, which is allowing weak division winners to get in with mediocre records. The NFL may have to do it with a 16 game schedule; a soccer league playing twice as many games doesn't have to.
Are there problems with playoffs? Sure thing. Do they make the winner of a playoff tournament any less 'best?' Who knows!? Because 'best' is a value statement that needs to to be defined.