I've played through KODP around 10 times now (mostly the iOS version which is more polished, but what's to love about the game is just as well included in the PC version). Two times the long variant and several short games. I feel like I have seen most of the random events now and also, which might hurt (further) replayability even more, I've got my strategy to success laid out pretty well, so my decisions usually don't vary too much from game to game.
That said, there is LOTS of replayability. Those playthroughs took me quite a while (especially the long ones) and I was really deeply engaged 95% of the time. You will experience vastly different stories (i.e. compositions of random events) with your clans.
KODP is in my opinion the best narrative-focused videogame of all time. Buy it and love it! :)