@jannem @mdione @andrewz hope there is software that better fits your use case---though as a digikam user I would not say that what you're proposing goes against the grain, because I do in fact use gimp and the internal editor together smoothly in my own workflow; usually I use the internal editor first to rotate, crop, and edit colours, and then gimp to remove splotches where I should have cleaned my sensor properly in the first place.
But, overall, yes, let 1000 flowers bloom.