Jack Sherrill's 3 syllables (1 + 2) hit the Hollywood sweet spot.
Jack's 1 beat vs. Sherrill's 2 create a natural cinematic snap.
Jack Sherrill's softer consonants cost it screen presence.
Jack Sherrill misses the alliteration hook that makes names stick.
Jack (4 letters) and Sherrill (8) have a slight length mismatch, but it reads fine on screen.
Jack Sherrill's uncommon phonemes make it harder for audiences to latch on.
Jack Sherrill has decent vowel richness, but stronger A and O sounds would lift it.