I think the Schleese saddles work for some horses and the fitters are key. They have a wide gullet with some horses really like. That can also give them a tendency to wobble around in the back, depending on the horse. My saddle fitting book (the one by Joyce Harman) cautioned about that (not for a Schleese, just for that issue).
I had a used one for a while. My horse loved it. I loved it. Her back developed like crazy and it needed adjustments. The fitters were fantastic. It was fit for one shoulder being less developed than the other and as that shoulder developed, it l became very uncomfortable for her. The tree did break and they replaced the tree no charge (used and per their website no longer under warranty). She eventually outgrew it which was good in that she was developing correctly.
The fitters moved on and the “new” Schleese fitters were um not confidence inspiring. So, my take is when they fit horse and rider, they are very very good. The rest of the experience depends on the fitter. J was very professional and helpful.
A friend of mine had four Schleeses and loved them. She now has a custom saddle from another brand for her current horse.
I like a lot of room in the saddle, a flatter seat, and no blocks. I found a Dover Circuit Premiere that she likes with a spring tree and wool flocking that has helped and found my horse had some issues I hope we have fixed (rehabbing now).
I wonder if warmbloods have been bred for such bigger movement that saddles are harder to fit. I also wonder if saddles fit too well and there isn’t enough room for full movement and body changes.
I noticed my oldest saddles have slightly wider gullets than my later saddles and now there are different gullet sizes. Some fitters say they don’t need a wider gullet. Some say they do. My experience is just to try to find something the horse and I seem to feel comfortable in and find the best fitter for your horse that you can.
Good luck.