Seems like a decent idea, but aren't rearing horses + heavy shields good enough? I think heavy shields need to be better vs. elite cav/knightly heater in some areas, especially against bolts. Right now, they're really unappealing.
I also feel that 1h/pole hybrid is better than a throwing hybrid if you're solo, especially since anti-cav requires little/no wpf investment and you don't need to spend any extra skill points. If they're kiting you, just get more ath. A group of throwing hybrids together, however, are extremely effective.