The main difference between the Sion and Galio VUs comes down to one simple thing
The Sion update took a goofy and archetypal character and turned it into a thematic badass with an intriguing look and theme.
This Galio rework seems to have taken a thematic badass with an intriguing look and theme and turned it into a really goofy and archetypal sort of character.
On the reveal thread on Reddit Reav3 said that Galio's VO isn't cocky as much as it is joyful. That doesn't make much sense, considering Galio's epithet is literally 'The Sentinel's Sorrow'.
I'm sure Galio's new kit and lore and such will be fantastic, but this VU just seems very off.
EDIT: I am still less than happy with his shiny-ness and happy-go-lucky feel, but since I will be playing as Gatekeeper non-stop I couldn't care less.