Apologies for the less than pro formatting...
Not my work, but if every promising Spurs youngster could follow the Holtby path (hello Tom Carroll, Alex Pritchard, and on and on), Spurs will be in very good position in the future. In a nutshell, Holtby faced challenging loans at a young age, and had to adapt and play multiple positions, depending on the loan. He was not an immediate success for Schalke, and had to prove himself at each level, while being young for each league. Granted, loaning players does not always work as each player is different, and maybe especially in England where the Championship favors physicality. I leave that question to those who follow England's lower leagues.
I think it would be a mistake to dismiss Holtby so soon.
I know they are very different players, but for fun, who will have the better career, Lewis Holtby or Tom Carroll?