Playing families with pets, toddlers, kids and adults with careers is a challenge when you rotate through each family and you know you have to return to each household within four Sim days or your toddlers don't learn skills, the kids don't go to school and the adults don't advance in their careers while not being active. And the pets are sick or starving with full bladders. I use a mod that keeps househod funds at a realistic level by donating more to charity which raises their good reputation level. The biggest challenge for me, is trying to find workarounds for the glitches and bugs, or adding new gameplay, better personalities, and fixing bugs through the use of mods. I wish this use of mods wasn't needed in order to tweak the game into something I can be happy with. But it has become the way of things with Sims4.
I test my skill as a player by adding certain rules for myself. No extra money cheats, adding mods that only alter gameplay, fix bugs, or end irritations. And giving each family a lot to do and accomplish requires a lot of effort and thought, too. I take advantage of the vacation worlds even though it takes me out of my comfort zone when I am focused on reaching a certain promotion, skill level, or things have become stale and repititious in a certain household. I use mods that do away with certain buffs so keeping my Sims in a happy mood takes a bit of juggling. There are ways to make the game more of a challenge. The trick is finding what will make it a challenge for you. We cannot rely on the teams to make the game more complex and challenging. The past couple of packs proved that to be a fact. It is up to us, the players, to find new ways of playing in a way that adds difficulty and surprises. The fact we have an entire discussion on this forum devoted to mods clearly indicates EA is aware Sims4 needs help, and has made it easier for players to openly discuss mods and share how these mods changed their game. There are many player-created challenges that are fun to play, and can keep a player busy for weeks. I stopped expecting the teams to bring the kind of gameplay I would like to see, a long time ago. It isn't going to happen. Not in Sims4.