I like it
In fact, it almost makes me recall the days of MoM, when heroes-errant would drift about and offer their services... and no matter which race you played, you could always hope that your favorite hero would pay you a visit!
Province-specific hero availability would be even more interesting. And incase Mr. Parker hasn't made it complex enough, the tax rate, unrest, and dominion strength should be factored in to the probability of a provincial hero supporting you
-Cherry