No regrets at all. I have work benches down one wall and cabinets above to. I like to have the option to rearrange things and add as needed. No issue with extra dust. You may also consider a dust collection system to help.
I know you have changed plans now but I'm new and just reading this. I originally was planning to build a 20 by 20 shop thinking it would be sufficient but after a year of planning and thinking more I ended up building a 40 by 40 shop. Which was great but after about 4-5 years I figured I...