I think MiW's comments about philosiphy are accurate. This isn't specifically talking about Caldwell but talking about football in general.
Having posession is good in principle but utterly worthless if all the posession is in your own half and you have 60%+ posession with zero shots while the opposition have 10 shots with the 40%.
Passing out from the back is good in theory, but it's utterly pointless if you lack the cohesion and method to get the ball into a useful area and just have your keeper kick it to defender and after a couple of uncomfortable passes lump the ball long in a panic due to the opposition pressure.
It feels in reccent years like some managers seem to watch Barcelona or Dortmund or someone like that play and seem to think passing the ball so much or high pressing is the key to their success and try to replicate that. But they don't seem to realise that Barcelonas passing game isn't effective because they have high posession and number of completed pass stats those are the by product of the movement off the ball, their pressing, bravery in posession, their tempo, the advancing full backs, creating overloads, the little triangles they uses, etc that allow them to make their passing game work - yet those attributes don't appear to be replicated anywhere near as much. Same with Dortmund the most recognisable aspect of their game is their pressing but it's not the pressing alone that makes them succesful. Those teams have talented players which makes playing their way easier but those players wouldn't do what they do automatically they need plenty of coaching to make their style work - yet it feels like managers focus on getting those passing stats up or getting everyone super fit to do nothing but press which doesn't actually help on it's own, rather than working on getting the movement and other things in place as well which is what will allow them to make that style of play work.
Having a prefered style of play is what all managers have, but when a managers (especially younger ones) start to talk about their philosiphies i think they can run the risk of making their preffered style of play into their identity. They can get too invested into a certain approach that it makes changing harder as it can feel like betraying their core beliefs. If you have been around and enjoyed success like Klopp or Guardiola have then they probably have a point, but for a young manager i think you need to be a lot more flexible and adaptive and i dont think pinning down yourself to any set philosiphy is a good idea when you need to work out what works for you.