Pretty sure maniac didn't mean any disrespect tho...
Your gf does have some gorgeous feet, and however ticklish is she doesn't make you any less lucky for having someone to share your fetish with, so kudos on that!
It could be the mood or whatever other reason, but I've also massaged fairly ticklish feet and in those times the girl tends to be a lot more reactive. Maybe she's used to your touch and so she can shows more of her ticklish side when made nervous, but as on the video, yeah, I'd stand with maniac, she seems cute and giggly, but overall I'd say at most a 5...
But then again, only you'd know, and it doesn't make you any less fortunate!