I would rather have "more to do" than a lot of difficulty. I like the "choose your own adventure" approach. I would take optional challenges which is the direction that they are usually going in. I also like being able to decide whether something is significant or not.
I think optional adverse events and the ability to switch on more negative consequences might make sense. Sometimes you might want that and sometimes you don't. As others observed, they are accommodating a lot of different types of players. I would take some challenges but I don't want a paint-by-numbers approach.
For example in TS3, I didn't like how an affair would basically always result in a bad reputation spreading around. While I'm not playing tons of affairs, I like to have more choice about how situations are handled. Sometimes that means a divorce but sometimes maybe the couple wants to work it out privately. No, I don't play like that a lot but I don't want the game to dictate the same response each time. I think there is room for more romantic gameplay and different romance styles including consequences but I actually did not like how heavy-handed TS3 could be at times. I'm not looking for a repeat of everything in TS3.
Adding some unpredictability or challenge? Sure, I'd want that. Generally, I like playing with happier sims so if they add a different mode for other players, I'll be fine with it. I don't think it is about making the game easier or harder though, more so, it is more about playing with different types of challenges. The optional lot challenges are a step in the right direction.
I will also add that I really would like "more to do" both in terms of gameplay objects and directions in which to take the game. I think they have been adding experiences that help with that but sure, sometimes I am looking for more. There could also be overarching themes for a household. The main thing is that many people play differently so we should not try to force everyone into the same playstyle.