And I don't just mean "prove it with another team"
He seems very good at getting the most from average players; and can bring players to the fringe of international rugby; he's proven this with Francis, LCD, Williams, Armand, Ewers, Simmonds, Maunder, Townsend, Slade, Nowell; whilst even the likes of Jonny Hill, Woodburn and Devoto getting mentions in dispatches.
But can he actually take a player and make them great; of the above list, I'd say that LCD, Simmonds, Maunder, Slade have the potential to be international greats, whilst others (Williams, Nowell, Devoto) have the potential to be solid international regulars; of the lot of them, only Nowell can really claim to have fulfilled his potential so far.
LCD has been let down a little by continued question marks over his throwing (about which I know less than nothing) - he's a 24 year old hooker, he has time, but should be further along by now.
Simmonds has been let down by being played out of position, he's a specialist 7 through age grade, with 1 season at 8, whilst playing alongside 2 backrow partners who both seem better suited to 8 than he - he's young and has time.
Maunder just hasn't had the game time he needs to progress - he's young as has time, but should be further along by now.
Slade has been messed about positionally; never quite earning trust at FH, and never being tried in his most "natural" position of IC - he seems to have stalled, he's been on the scene since the last RWC, he's 25, he's been selected 11 times, and has only impressed in one of those (his debut) - he's fast running out of time to be anything other than emergency injury cover at international level; despite his messianic status a couple of years ago. He's 3 days younger than Ford...
It's good for his club - he can get these players to almost-international standard; meaning that they're very good, without missing chunks of the season; but an international coach's job is to take those players and have them maximise their potential.
My apologies if this is not particularly well thought out; it's only really ocurred to me over the last couple of days in a discussion over on the Bath forum. I still haven't decided if I agree with the theory or not, let alone whether I have enough to defend it to others.