Florian Vorreiter wrote:...Also, I don't see how an instrument up to $ 4,500 should be harder to play than what you currently have...
A couple of additional points which may possibly be relevant.
A a concert instrument shouldn't be necessarily harder to play, but many professional players do prefer a high action, which in turn allows them to get more out of the instrument than an amateur might. I've heard amateurs and then a professional play the same guitar one after the other on a number of occasions, and they might well have been different instruments.
Another factor which can be important is that good guitars are usually very resonant and have good sustain. For a player used to a 'dullish' factory guitar, it can seem like there are all sorts of extraneous noises happening while they're playing and it can sometimes take quite a leap in technique to control it. I recently had a player tell me she was sure there was something wrong with her guitar (made by a top UK luthier) because of this.