Ditto with my Lowden. The only instrument I've heard which sounds better was another Lowden - at three times the price. I still play the occasional guitar in shops, but not seriously. It's the difference between going out on the pull on a Friday night or idly watching the pretty girl who's crossing at the lights in front of you.
Having said that, the reason I traded up was mainly because my old plywood Crafter's frets were worn down. The Crafter is still a nice instrument, and I still play it occasionally. Five years on, it still needs a refret though - one of these days I'll get round to doing it. As much as I love the Lowden, if I'd got the Crafter refretted then I would still have been able to do just as much with it as I do with the Lowden.
Guitar-wise, there are things that'll improve your playing. But they are simply having suitably intact frets (ie. not worn down), having good action on the instrument, and to some extent having a neck that fits your hand size. The most important are the first two, and they can be achieved on just about any guitar so long as it doesn't suffer from some physical woes like a warped neck. If your guitar's neck setup works, to a large extent it really doesn't matter what it's attached to, because you'll still be able to play just as well. You might not get the same volume or tone, sure, but that's irrelevant to the quality of playing.