Well, you feel that taking so many players who are not the finished article (this can mean all young players.... they are all by definition still learning) is a mistake in itself, the polar opposite to this is the QPR option of signing big name established talent.
As we well know, neither system is perfect and the middle grey area is probably the best route. Personally, for me of the two extremes its better to sign only players that have the potential to get better then ones that will only get worse and also lose their value (and the club millions) in the process.