On the off-breed/outcross side of the discussion, I’ll admit I don’t understand the recent Friesian/DHH/ASB obsession but I’m predominantly H/J so they really don’t suit my tastes. However, there is a HUGE need for safe and sane born broke types that can jump 3’ and under and be semi-competitive in local As and opportunity stuff. I’ve seen two off-breed types be very successful at this job repeatedly:
Appendix QH and Half Arabians.
The half Arabs have the more refined WB look with the right cross being a catty jumper, and the Appendixes can be surprisingly nice movers. But, since these are usually bred for the breed circuit, they aren’t consistently the USHJA type. I think if someone wanted to, they could easily (with educated choices and luck) make nice lower level hunters with those crosses.
Personally I still think a TB is the best “non-WB” choice, and if I chose to start a breeding program I’d be getting the highest quality TB broodmares I could and crossing them with appropriate WB stallions. YMMV, of course.