I think a lot of the simpler filtering is understood just fine in spatial domain. It's just that a lot of the filtering isn't even taught in that context either

I think a lot of the simpler filtering is understood just fine in spatial domain. It's just that a lot of the filtering isn't even taught in that context either. Hell, a lot of what is called 'filtering' in the instagram sense doesn't even touch frequency domain - they're global manipulation of color balance, contrast and levels. There's certainly space for improvement - it would certainly be nice to expose the underlying frequency domain components when manipulating filters, but I really think that you've overstated the level of lack of cohesion in Photoshop terminology, especially as a case for major UI changes. And certainly, anyone who -has- knowledge of Fourier methods will also understand that by its very nature, spatial formulations of filters are every bit as legitimate as frequency domain formulations. Which one you should use should be based on whatever is more convenient. A nice box/circle blur is certainly easier to reason about than its frequency domain counterpart.