OK, I hit a lot of points in that last, long post. Let me see if I can keep this relatively concise...
On paper, the Yankees should wipe out the Giants. The Giants had a great year and won 96 games, but the Yankees played at a 99-win pace against the AL team they did worse against, and were at a 108- or 117-win pace against most teams. So, let's try to look at whether I'm overlooking anything that might indicate we're underestimating the Giants.
Team Stats Comparison: I talked about how the Yankees and Giants fared in their own leagues, but let's go one level (or maybe two levels) deeper and try to avoid the Rustlers Effect that I fell victim to in 1921. AL teams had a road ERA of 4.53 and a road OPS of .719. Visitors to Yankee Stadium had an ERA of 7.36 and OPS of .888. AL road teams not facing the Yankees had an ERA of 4.23. The Yankees had a road ERA of 3.79, nearly a half-run better. If we do this for the Giants: NL teams had a road ERA of 3.76 and a road OPS of .724. Visitors to the Polo Grounds had an ERA of 4.46 and an OPS of 0.777. NL road teams not facing the Giants had an ERA of 3.69. The Giants themselves had a road ERA of 3.90. Maybe not demonstrably worse, but certainly not demonstrably better.
The flip side (or maybe it's the same side, actually) is runs per game by the offense. AL teams scored 4.64 runs per road game. The Yankees scored 5.68 runs per road game. Non-Yankee teams scored 4.70 runs per road game not involving the Yankees. So the Yanks scored a full run per game more. NL road teams scored 4.46 R/G, the Giants scored 4.67 R/G on the road. Non-Giants teams scored 4.49 runs per game vs. non-Giants opponents. Here the Giants are 0.2 runs per game better than average, which pales compared to the Yankees.
Individual Difference-Makers: Cristóbal Torriente turned in one of the greatest offensive seasons we've seen in this league, setting the single-season record for home runs and finishing with an OPS+ of 168 and just shy of 7 WAR. He's only 3rd in WAR among World Series participants, though--his teammate Marty McManus outpaced him based on his defense (and a good offensive year too) and Harry Heilmann led all other Yankees and Giants this year with a WAR of 7.5.
Nevertheless, Torriente is the big name and, I think, the best player at the Series. In contrast to most of the World Series the Yankees have been in, the top players by WAR are dominated by the NL team--Heilmann is the only Yankee in the top 4, with Ken Williams following Torriente before a string of 6 Yankees in a row round out the top 10. Looking at OPS+ and deciding on an arbitrary 200 PA (since so many contributing Yankees were part-timers or injury replacements), Torriente leads the group, with Heilmann and Ken Williams following, the injured Charleston and Collins following them, and then Cobb, Cy Williams, Bullet Rogan, and McManus all in a virtual tie at 120.
Getting into the weeds a bit more, Torriente seems to have a reverse split and fare better against lefties than righties, while Ken Williams has a normal split.
If we go to pitching, Vance is pretty clearly the best on either team, both in terms of WAR and ERA+. Flame Delhi, the Giants' ace, is closer to Vance than one might think given that he was "only" 22-11. Vance had a good FIP (again, with Delhi surprisingly close!), but it was the Yankees relief corps who led the way there, with Ruether, Mogridge, and Curry all besting Vance while pitching 30+ innings. Mogridge also had a better ERA+ and had a sneaky-good year out of the pen, including a league-leading 13 saves.
Other than Delhi, the Giants' pitchers are not quite so impressive. Sanders, Hampton, and Hall are currently listed as the starters for Games 2-4 (though that could change), and the Yankees starters (Rixey and Faber with Vance in a 3-man rotation, pending how things go) match up well or better.
A Watsonian Word: The city of New York would no doubt be alive with excitement, even in comparison to last season's Robins-Yankees contest. The Giants are still in a lot of ways the more prestigious, better-rooted team, and they drew nearly as many fans as the Yankees did (and brought in rather more revenue). There's more fan interest for the Giants. Can the Yankees keep it together with the injuries and perhaps less urgency than a Giants team that hasn't made the World Series since 1913 and hasn't won one since 1905? Or will the chance to match the Rustlers' record with a third consecutive championship and the drive to finish off a dream season be more than enough to carry the talented pinstriped crew to victory?
I'll also note that two players from that 1913 Giants squad are on the team for the 1923 Series: Art Fletcher, who's been in New York the entire time, and Milt Stock, who's returned after time on other teams.
Prediction: I tried to talk myself out of a Yankees victory being inevitable, but I can't. Things happen, the Yankees could have a few bad games at an unlucky time. But I think by far the likeliest outcome is a Yankees win. I'll say 5 games to be conservative, but a sweep wouldn't surprise me at all.