I haven't seen all of Mitchell Ryan's Burke, but I think he was written as a different character from Anthony George's Burke, I can't blame Anthony George for what the writers did. There's a scene somewhere in the first six months in which Burke, talking to Vicky, thinks about what his life would be like - how much better it would be - if he didn't have the need for vengeance. I've seen the scene only once, several months ago, so I may have gotten the details wrong. But it made Burke interesting, and gave him possibilities. Once the vengeance issue was resolved, however, Burke did not take up skydiving or anything; he just obsessed over Vicky. Maybe there's a certain consistency there - Burke being serially obsessive - but I think the original Burke was better than that.
I used to think that Mitchell Ryan would have been a fish out of water in 1795, but then I watched the revival series, and saw Sheriff Patterson become Andre Dupres. If that casting could work, then anything can.