The game's overall difficulty level can be adjusted in other ways, but the one event that's difficult to dismiss is Attrition: when a territory is overcrowded, you (and everyone else in the territory) lose population until it's below the limit. This has been organic to the game since its very earliest days, and the ability to overload a territory, but with some risk, affords flexibility -- e.g. to let a player amass a huge army for a crucial attack, or to massively produce an urgently-needed resource from a single territory. The simplest solution to removing the event is to also remove the ability to overload a territory, but that changes the game in a way that probably isn't devastating, but it would be less satisfying.
Thinking about this forced me to think about the way the game handles population growth and pressure in the first place. From the beginning, population growth has been voluntary, and costs crops. You can only add population to territories you own, which was supposed to create an incentive to expand your empire early (which makes the empire itself more costly to manage). This happens to some extent, but what seems a bit more common is that you just max out your population to fill the territories you own, and then you don't really grow much after that. That's ok, but it's perhaps not entirely historically plausible.
This led me to the idea that population growth could be automatic (so you can't avoid population pressure), but infrequent (say, once per epoch). If overcrowding didn't cause "attrition", but instead just forced you to take on Unrest, then perhaps this provides two forces pushing players to take on Unrest -- on the one hand, overcrowding may become difficult to avoid, and it may be easier to take the Unrest than to reconfigure your empire so as to avoid it; but on the other, particularly early in the game, you can't grow your population fast enough to produce enough to do what you want to, and you may have to use forced production, and accept the consequence (Unrest).
It would treat population, and "headroom" in your territories, as a resource in a way that the game hasn't previously, and it might be interesting as a way to retain some of the features that the events will no longer provide, and also to create an additional source of interesting and challenging considerations for the players.