I get the xG point you're making, but think of it as a reason to look at him a bit more. Nobody has ever been relegated with a boss xG to the best of my knowledge (only one I'm vaguely aware of would be WBA in 2018 where they finished bottom despite having an xG which would have had them 13th with a par performance).
Brighton's performance last season would have had them 5th by the same metric. It isn't a reason to appoint him, but it's an indicator that he may be doing something right and to take a closer look to see if the way he sets teams up etc may translate well with a better team. One point I'd make re Potter is despite the xG stuff, the thing I like about him is that he's demonstrated an ability to change the identity of a club whilst not suffering on the pitch (plenty of managers have tried to play nice football and got webbed because of it), Brighton's defensive record has improved under him even if you ignore the xG stuff. Everton are crying out for an identity.
I absolutely agree we are crying out for an identity, I said the other day the only time in the last 6 years I could remember an identity was under Martinez.
I just don't see it with Potter, but I might be wrong I would admit that. I get what you are saying but Brighton didn't finish 5th, so its impossible to say he is great if they finished 5th I might sit up and take notice. They didn't though.
I get the xG stuff, however to me it is a bit fictional, no-one will look at the league table and go, "ooooh Brighton finished 5th on xG" They finished 16th. xG might be down to look or crap finishing, its not exactly things we are blessed with at Everton - I want something more tangible then xG. Thats just me though I get people who base the ideology on statistics, but 5th on xG or 16th in the league I know which one I will look at.
I don't watch enough of Brighton to have much more of a rounded view on their play, but I just think he isn't ready for a club like ours right now.