I know nothing of Steve Rother, however if you are looking for less aggressive or pressured methods then there is Carolyn Resnick. KFH is great but it's not a system really. It's more about a presence, so it's very difficult to 'teach' especially if not 1-1. Similar to Nevzorov in some respects though opposite poles in other areas.
I also find that the KFH approach is most close to perfect, however it works better and faster with totally unknown horses than with a horse who you have had for some time. I found it much easier to find my way with horses I had never worked with before than my own horse who had gone through 4 levels of NH with me.
A lot of this is because the 'healing' as he puts it happens in literally minutes if not seconds with a new horse, because you have no baggage together.