I was one of the pessimists during the ALDS and so have no great claim to insight.
That said, the Sox beat the 100 wins Yankees at their best even though Happ, Severino, and Sabathia weren't at theirs. And they did it with starting pitching, timely hitting, and just enough bullpen. And the better manager, beyond question.
ALCS will be 2017 ALDS redux--when the Astros took 3 of 4 with Sale losing twice, Pom once, and the bullpen, mostly Price (of all people), getting the one decisive win. The Sox lost game 5, but it was 5-4, and in that game Sale gave up 2 in relief and Kimbrel 1 in relief.
My point is, this year's Sox, despite concerns again about our bullpen, is a lot better than last year's. When your rotation gets three good starts, two of them in NY, against the Yankees, you ain't pushovers.
But neither are the Astros, who have the best pitching in MLB. Right now, I would call the ALCS a toss-up.