LTNman - I think you are being a bit harsh on Luton compared to Gatwick.
Gatwick has the luxury of far more acres of land and a longer runway. 3 years ago, Luton was cheap and nasty. The terminal extension with the new shops has tried to target a slightly wealthier passenger.
However Luton seems to feel far more overcrowded than other airports leading to the grotty feeling overall. This will only really be resolved by the airport having a bigger area of land to use
That said, most airports would consider overcrowding and too many pax, to be a nice problem to have