like @Rashidix mentioned, there are some elements somewhat similar to what you describe (adventures, in this case) and I imagine it could be possible to add more complexity to the adventure system, similar to the events you describe... maybe something like "choose your own adventure" style: "Your hero encounters a wild tiger while on his adventure... does he: try to tame it... or does he try to kill it" with certain percentage of maybe taming it, which results in a tiger added to your village but failing to do so means losing a big percentage of your health and returning empty-handed. I could see that happening maybe, if there was enough interest.
However, like @Rashidix said, Travian Kingdoms is not really oriented toward that kind of randomness and I can imagine many players being angry if we added any additional random factors to the game. I just want to point out the difference in the combat for example: In Crusader Kings II battles are an unknown... you don't know if the wind, the terrain o your generals are going to make you lose the battle and it's hard to predict when forces of similar strength face each other. In TK, on the other hand, you have a combat simulator that, provided you have all the data, can give you a 100% accurate prediction of the result of the battle and the fact that you can predict such things so accurately, plan with them and do the math is a core feature of Travian Kingdoms.
I personally like the idea of a "grand strategy" game with random factors and different beginning traits for players (your character is... "son of a farmer!" therefore provides +20% crop!) that is always online and where every other character is a player, but definitely not for Travian Kingdoms. The core aspect of the game is too different to implement anything like that and it would mean basically changing every aspect of the game. Thanks for the suggestion though Let me know what you think about more complex adventures.