There is no evidence to date that Barry can bring anything to Rangers as a first team coach or as a manager at this stage. He's certainly nothing like Gio, and I doubt his personality would complement the existing team, even if his track record was good enough.
It'd be interesting to get him on RTV as a pundit, but that's as far as I'd take it for now.
He's still very young in managerial terms, and has plenty to work on to improve man management skills (from what I hear, but this is 3rd hand information).