I suggest they add a 'hard mode' game pack.

I never had a problem with making my sims' lifes harder, so I wouldn't pay real money for a pack that automates what takes scribbling down a few house rules. I think that would only appeal to the "I don't want to make my own story" crowd that waits for the game to tell them what they can/should do next. Or maybe if you play with free will on, and your sims grab free meals all the time despite you having said they can only cook if they own all the infredients, I suppose that could be annoying and immsersion breaking. But still, for the price of a gamepack I could have four kits or two SPs that actually expand my experience.

Maybe a free update or a kit with some penalty traits like slow learner, wimp and the like instead of a GP? Sims could start with a number of points for helpful traits like in an rpg, and taking penalty traits would grant them more points to spend on helpful traits. But sims shouldn't be required to spend all their points, if a player wanted only unhelpful traits, that should be possible.