Hmmm....your ideas, OP, seem sort of exclusive to some potential boarders.
The small paddocks and small group turnout idea is not ideal for some horses. Take our 6 yr. Old OTTB as an example. He is a psychotic alpha...extremely bossy and loves to herd the herd....when he was in a herd in the past, everyone would give him his space and he often would herd them around and around. No one was seriously injured by him but that was because they would all submit...but newcomers were in for a time as he taught them the rules. Which included charging at them with bared teeth, etc. Even in a small group of 3 or 4, if confined in a small space, the others would not be able to give him the space he requires nor would he be able to herd them, so fighting would result.
Our OTTB also LOVES to run... he will often break into full gallops for no apparent reason and just run and run...till he's breathing hard and sweaty.
In a small paddock/pasture he would not be able to do this.
We also have special needs regarding both our horses. Our fat draft needs dry lot as her pasture time is limited, especially in the spring....
Our OTTB also should ideally be in private turnout due to his aggression with other horses.... where we are at now, Beau and Epona have three pastures which total 23 acres....even with the large pastures and lots of room to run, he still sometimes has aggression issues with Epona once in a while.
Also, I would definatelly want stalls for our two horses available for use when we needed it. And not just for injury or illness. Our OTTB is an "indoor" horse, also known as a hothouse flower.
he does not like rain or snow. And will refuse to go out if it is raining... he also does not like flies in the summer and will come to the barn door and stand to be brought in
So, where we are at now is a private residence with 23 acres of pasture and 6 stalls and a dry lot. We are the only boarders and we have the place to ourselves. We do not have an indoor areana but since we just do trail riding, we don't need one....there are tons of trails on this property. We also have a heated tack room, a heated bathroom and hot and cold running water in the barn and in the bathroom. In the summer the property owners provide a 60 inch barn fan for our horses. The property owner will bring them in or turn them out as we request and does remove blankets when needed. She also fills buckets and throws hay when asked.
We do our own feeding regimen in regards to grain or supplements and provide our own hay.
So, being unwilling to offer stalls to those who want for their own preference or who have "hothouse flowers" may limit your clientelle.
Also, not having a dry lot will limit your availablility to those with fat horses or those with metabolic disorders...like IR
Also, smaller paddocks limits your acceptability to those with high energy horses or younger horses that need room to romp and play.
Smaller paddocks can also increase aggression in small groups as some horses need their space and if a herd member crowds them wil react negatively.
Just my thoughts....as someone who needs stalls available and who has two special needs horses.