Ted,
Sounds like you have put a lot of thought into this and I think you are on a good track with your project as it relates to your stated goals. I like the idea of moving water to wetland without filtering first. Like you, I think this requires less maintenance and energy. In the end, that equals cost savings and more enjoyment.
It's similar, very much so actually, to some thoughts I've had but I think I was going a bit different direction with it (thinking about how one could make stream for the stream's sake using a high volume blower).
For a tiny pond project I've been contemplating (1/8 acre), after some thought, I decided the best solution for my purposes would be less water movement. My interest in the wetland filter had more to do with wanting a wetland for amphibians and a forage reserve that would exclude predators and that would also provide some water feature as well. Some do this to make the water quality good enough for swimming ... that's pretty cool too.
There are a number of ways to deal with nutrients and this is a very good way do that.
Lately I've been researching ways to do this with organisms, particularly with macro-organisms that can meaningfully contributed to the food web. Harvested fish in this case represent sequestered nutrients that flow out of the pond ecosystem. I think a really good balance of organisms along with harvest may go a considerable distance in controlling nutrient buildup and eutrophication.
