Indeed, the shiny leaves are basically lost in AO. In my area blackspot pressure is very low, so I can’t really assess that, but AO doesn’t seem to mildew, which is appreciated.
When I was looking into the topic of laevigata hybrids, I found a post by regretted forum member Karl K where he quoted Van Fleet’s thoughts:
“A very striking common feature of the hundred or more Cherokee hybrids we have grown is the entire disappearance of the characteristics of the mother plant. In no instance were the hooked prickles and narrow glossy foliage of Cherokee reproduced.”
But still, I hope you will try with laevigata and I wish you success!
The rest of the laevigata thread may be of interest to you as well, here is the link: