I don't want to break the game! - I just think everything goes towards nobles becoming more noble, with no mechanism to radically diminish this. I agree we should look to being part of a realm, I just feel there should be facility for a family to be stripped of rank and have a wholesale fall from grace.
I'll probably sink my infiltrator to zero honor/prestige eventually (immigration happy mixed with failed attempts at nefarious activity). That is the only way I can think of to really make a noble...less noble. Hell, if you realm hop enough...you might as well be rogue.