Of course they are. I don't think anyone has argued otherwise. They'd be a good team in any division. But it is also true that the AL East has been a monster of a division. This year the top 4 teams are 4 of the top 6 teams in the AL, and 4 of the top 12 in all of baseball. It's absolutely stacked, and if you put any of them in a lesser division, their combined winning percentage would likely be such that NYY, Tor, TB, and Bos would be 4 of the top 8-10 teams in all MLB. And they're all in the same division.
It really does matter, especially with unbalanced scheduling.
In some ways it's not very different than pre-wild card (or 1 WC slot). Back then, you might be a great team, and even have a great record, but you may not get in if you're in a tough division. Access can be blocked by a better divisional team above you. Meanwhile, a shrub from another division gets in.
Here, with the unbalanced schedule, the outcome dynamic is smiliar, but the way it plays out is different:
- If talent is spread among the 3 divisions, the teams with the best records will generally be the best and get in.
- If talent is strongly clustered, a good team in the tough division might get pushed toward .500 with the unbalanced schedule. Put that same team in a weak division, and under the unbalanced schedule, they get more wins out of the same effot. Because they're playing against easier teams.
In terms of outcomes, you can get a good team with a poor in-division record missing the WC clustering. Meanwhile you can get one or more teams from weak divisions compiling a good W-L record against the dreck of their own division - and so getting a WC spot.
Maybe the biggest inequity would be a very strong division (AL East?) and a weak division in the same league - say with 2 teams that are essentially punting. One or two teams in the strong divison get suppressed records. One or two teams in the weak division get a huge boost.