Exactly ... I'd say more 80 percent of everything you ever want to do with an image ... the other 20 percent is probably stuff that isn't worth doing anyway ... I use GIMP all the time and it's the image editor I use the most often
GIMP is pretty good, but I think the expectation that it should fully replace Photoshop for professionals is wrong anyway. Use whatever you feel is the best tool in the toolbox for the job.
gimps ui is just less intuitive. I have no doubt it can do everything photoshop does for people who use it regularly, but as someone who just wants to edit some images occasionally, its challenging to learn (and relearn) its quirks everytime. all of that could be fixed by just changing the UI though.