I've got a question because I'm curious: what made you guys differentiate strong and weak claims? Was it a spontaneous idea or did it arise from testing or from forum discussions (I remember musing something about that because it mattered to me)? I love it! In fact, I hope you could make something like a rating or grading system, for example percentile.
What are the criteria for strong and weak? Is it e.g. just the passage of time or are claims of younger brothers weaker, claims of cousins even weaker etc.? What about elective monarchs who don't win the election following their usurper's death? (E.g. Count of something is elected King of Denmark, subsequently deposed by a huge duke of Skane, who dies 1 year later, and the rightful king fails to win that election. What about the claims of his children who would've been entitled only to a better shot at election but not directly to the crown like in an hereditary monarchy?) Is there a mechanism in place to detect that a claimant has a better claim than the current holder and modify some things accordingly?
What about prestige/piety for pressing spurious claims and winning? For example, in my current game as Poland, I have a mayor whose dad was a generic baron married to a Princess of France (possibly widowed by someone more important). Suppose if all Capets died and the kingdom became a sultanate, I should get a huge piety/whatever bonus for digging up a forgotten heir, King Arthur style. On the other hand, pressing his claim against the last chain of first sons or first sons of previous kings of France should probably get me excommunicated and DoWed by everybody else than merchant republics, not to mention massive penalties for that new king. I didn't do it but if I did I shouldn't be allowed to get away with it, I think.