Goalkeepers look better when you're not seeing them week after week. You don't see their little issues they have when you're not a fan of their club and only watch them sporadically.
When Howard was coming towards the end of his time with us fans of other clubs still thought he was brilliant for us. But we knew he was well on the downward curve but looked excellent at doing star jumps. Even when he was at his peak they didn't know he was beaten regularly from distance but we did.
Henderson, or whoever else you want to name as being better than Pickford, will have issues and negative points to their game as well but you'll only find them out if/when they sign for us and then you'll moan about those things too.