We all see what one great day can do for a hitter in April vs August, or what one bad day can do to a pitcher in April vs August.
Wild swings can occur over one pitch.
The big difference maker in your whole Wong vs McGuire focus is that they have caught pitchers at wildly different sample sizes, and the ones that are somewhat balanced are still too small to consider as noteworthy, but it might convince you to lay off McGuire.
(Please don't assume that because I am posting these numbers, I think these sample sizes are significant enough to even begin to tell a worthwhile story about their skill sets as catchers.)
Somewhat balanced sample sizes:
OPS Against
Crawford
.310 w McGuire (29 PAs)
.891 w Wong (45)
Pivetta
.799 w McGuire (22)
.742 w Wong (42) Close to even
Winckowski
.377 w McGuire (19)
.641 w Wong (36)
Brasier (some pretty tiny sample sizes, here)
.880 w McGuire (30)
.465 w Wong (18)
Kelly (tiny sample sizes)
1.194 w McGuire (19)
.381 w Wong (15)
Schreiber (tiny samples)
.574 w McGuire (16)
.681 w Wong (23)
Bleier
.866 w McGuire (16)
.686 w Wong (18)
Jansen (Tiny SS)
.220 w McGuire (14)
.844 w Wong (10)
Martin (Tiny)
.482 w McGuire (11)
.918 w Wong (18)
Out of Balance
Sale
1.061 w McGuire (64) His most caught pitcher (tied w Kluber)
.430 w Wong (25) His 2nd least caught SP'er
Kluber
1.045 w McGuire (64) Tied for most caught pitcher w Sale
.544 w Wong (19) His least caught SP'er
Ort
.803 Wong (33) Not a big differential, here
.871 w McGuire (13)
One-Way Pitchers - VERY NOTEWORTHY! (No McGuire innings with these two!)
Houck
Zero PAs with McGuire
.728 w Wong (58) His most caught pitcher.
Whitlock
Zero PAs with McGuire
.819 w Wong (44) His third most pitcher caught
Bello (No Wong PAs)
1.289 w McGuire (18)
Zero PAs w Wong
It's easy to see why we shouldn't read anything into the disparity, no matter how grand.
How many pitchers, who have had both catchers catch them do significantly better with Wong vs McGuire?
I count 6 to 5. If you take away the unbalanced, it's 4-3 in McGuire's favor.