Trust me, when it comes to barns and set ups, you are far ahead of most people.
The amount of land is always a huge plus.
Having the lot there outside the barn that leads to pasture is not a bad thing and can be used for a dry lot for a horse that starts to get overweight.
My barn is actually 40 years old, and while dusty, is more spacious then most of the barns I see today with 8 enclosed stalls, with a hall way down the middle.
The biggest problem I would like to solve one day is to put doors on the outside to easily scoop a stall when needed instead of shoveling crap every day as I currently do, so trust me when I say your stall setup is actually pretty good, and I see more and more people going to that syle now instead of the old style like I have.
Overall it looks pretty good, just a little orginization, but as someone else said, its easy to be OCD about a barn, and I sweep mine daily to keep dust down lol.
Good job. Hopefully you'll inherit that place one day...