Hi Bloomagoo-
I understand your point about height/stability. When I first got in I had a similar reaction. Turns out it was a matter of perception. I now stand up and paddle
full-force, turn around 180 degrees and sit with my feet over the side, all with no problem.
When I first motorized the Wavewalk I attached pontoons I had left over from a previous boat (Radisson Canoe). Now I shoot around the lake without the pontoons using a 2 hp motor at 8+ mph without them.
Maybe it's a little bit like a bicycle which, when you first get on you are sure will tip over. Two weeks later you're riding "no-hands". Suffice it to say, if you go to YouTube and/or the Wavewalk site you can watch
hundreds of videos of owners (not paid professionals) standing, paddling while standing, jumping, rocking, etc.
Of course you are right that you do sit up with your legs beneath you (and that's why its so comfortable). So while the saddle is 14 inches high, your feet are actually pressing on the floor of the hulls and are therefore
below the waterline. And since the boat drafts about 4 inches of water with a 200 lb paddler , your butt is actually only about 10 inches above the water. Finally, in a Wavewalk, 100% of the buoyancy is at the extreme flanks rather than in the center like traditional SOTs and SIKs. It is more stable than any SOT or SIK.
As to the back support, most users don't find any need for it as they constantly change positions (lean forward, lean back, lay down flat, sit straight, stand up, etc.). I on the other hand, really like back support so I either use a simple "easel" support that drops into any place on the saddle or I use a plastic lawn chair. You can see pictures of a guy paddling and napping from a plastic Adirondack chair if you go to Wavewalk/BLOG and run a search for "Lawn Chair".