I agree with you about Photoshop LE - it was "dumbed down" but I think way too much, and cluttered with stupid "user friendly" tools, which I simply found confusing, and non-intuitive. Photoshop Elements has most of what full Photoshop has, in a much easier format.
Photo Deluxe was another similar attempt to make it "user friendly" but I think it was just cluttered up with annoying "cute" things.
There are tons of other programs - the Microsoft one wasn't bad, but you could not tweak printer settings with it, and so it was a waste of time. I have at least 15 other similar programs, none of which I really like. They all had quite big limitations.
As I look at it, the biggest investment I can make is my time. It takes a good long time to learn a photo / graphics program, so if you are going to make that commitment, you might as well do it with a program that is going to be around a long time. Photoshop used to be a Mac only program, and most IBM users never even heard of it. A decade or so later, and all those other programs are dead, and Photoshop is really the only serious program (sorry Corel) - and Elements really is pretty easy to use. It should be a pretty reasonable "investment". It will be around a lot longer than most of these cameras, as you point out.
I am going to order the simple Canon UW case as you suggest!!
(If I had a dollar for every time a yelled at my computer while using Photoshop 2.0 I could buy a nice Nikon D100 for both of us!)