Here is my unprofessional opinion on muzzle crowns. Take it or leave it, but I also think the crown is there to recess the rifling a little into the bore in order to protect it from damage. I would certainly crown the barrel if I could. If unable to do it I think I would be fine without it crowned but I would be very careful not to bump the end of the barrel for fear of damaging the rifling. And I'm sure we all are careful not to do that anyway, yet it still happens. Once again, just an opinion that's not based on any known fact.
On a second note, why didn't you, Semi, contact Thompson Center and discuss your accuracy problems with them? Now that you have cut the barrel you may have voided the warranty.