What if the PPC bolt missed Ian Davion?
Give that one some thought for a moment. Think of the enormous impact Hanse had after taking the throne, not just in his own realm but across the Inner Sphere for the next few decades. His effects are still being felt a century after his death.
Consider this short list:
+Hanse agreed to the ideas of Katrina Steiner about peace, which lead to the alliance that eventually became the Federated Commonwealth. We don't know if Ian would have been interested in that idea or not- if so, it still looks very different, so this one is at best a 'maybe'.
+Even if Ian agrees to Katrina's ideas, Hanse likely never marries Melissa Steiner (why would she be offered up to someone who isn't due to take the throne?) Whether that means she marries Ian is questionable (likely though), but it means either way...
+Those five kids from Hanse and Melissa? You know, the ones that dominated Inner Sphere politics and battlefields alike for the next several decades? Victor, Katherine, etc.? They don't happen. Ian and Melissa, assuming we ship that couple, likely have a few kids of their own, but they won't be the Victor and co. that WE know. Which means the entire line of both Houses is muddy for years to come- after all, we're up to Hanse's great-grandchildren running things by the 3140s. We have to rewrite that whole lineage in both realms.
+No Civil War- well, okay, eventually it was bound to come one way or another, but not in the form we know it as, at least.
+How does the Clan invasion change? After all, Hanse surprised everyone with sending help to the Combine- would Ian have done the same, or let his ancient enemy perish at the hands of the Jaguars? Really, how would his own realm (assuming the FedCom still formed) weather the storm from the Falcons and Wolves?
Just a few thoughts, but it makes for a wildly different Inner Sphere through the pond-ripple effect- no realm is untouched by those changes. And all it would have taken is a single PPC bolt being a couple of meters wide of an Atlas' head...