Well, that just sounds like mortality sucks for you in particular. It's natural that new characters don't have a rich background, and they shouldn't automatically assume the positions left by dead nobles. That is why you make sure that when the older ones die, there are people around to replace them. Other people, not new nobles from the old family. In fact, the way your message comes across is 'Mortality makes keeping cliques around harder'. You complain that new nobles have no motivation to interact? That's just crap. They're the sons and daughters of your realm's elite, why the !@#$ would they not try to pick things up where others left off?
Mortality on BT did nothing good.
"That is why you make sure that when the older ones die, there are people around to replace them"? How on earth? "Hey guys, ignore this respected family, let's all just vote for this dude nobody knows!"
That's not what happens. What happens is that the more active and risk-taking are the more likely to die, and when they do, the vacuum they leave is usually filled with the risk-averse low-activity nobles who have been there for a long time.
You read it as you wanted to. In no way does mortality make clique-keeping hard, unless you consider a clique to be any group of people who play together. OOC cliques will not in any way be interfered by character death. Nor will strong cliques. Only loose groups of people regularly working with each other. In a game based on interaction, things like mortality that discourage it are not a step in the right direction.
Why not pick up where others left off? Now you are just contradicting your previous statement. In a tightly-knit ooc clique, sure, all ties will be instantly remade. Not so when it's a large group where people are just playing with each other and have just sporadic private contact. You know, like, what a realm usually is? A bunch of people loosely working together towards a common goal? With old characters, you can always go like "we fought together in that great battle!" or "you ran against me for that position I coveted!" Past experiences like these help stimulate interaction. When the realm is filled with people who are basically strangers to each other, that tends to decrease activity.
