ALOT of suggestions or ideas ....

Cooki3Ston3r​ there are a few things already available in some expansion packs, like log cabins. I find the best packs for building log/wood cabins are Horse Ranch, Outdoor Retreat, Werewolves, Enchanted by Nature and Adventure Awaits. It's one of my favourite ways to build.

A home theater can be possible with Movie Hangout, Get Famous and for an outdoor experience there's the Little Campers kit that has a large screen. You can also resize base game TVs for a bigger screen. There's a cinema in Growing Together at Anchorpoint Wharf which is a rabbit hole lot. Growing Together also has a treehouse for kids and the perfect items to build a water park. There was a base game water park in the Library from years ago called Dino and Turtles Water park if it's still there. I clear my library to save space so I can't check that unfortunately. I made one in the Gallery that I called Whalebert's Water Park using the Growing Together items and quite a bit of Eco Lifestyle build content.

There are functional ceiling fans in ceiling decorations but it requires the Seasons pack to actually affect temperatures. There is a base game one, Dizzy Palm Ceiling fan as well as some added with Island Living, Desert Luxe and Industrial Loft and I'm probably forgetting more.

Strangerville adds a military career with collectable military medals.

City Living adds earthquakes with the Quake Zone lot challenge.

I'd like to see more tattoos, I've been hand painting some myself to add more variety with the paint mode from Business and Hobbies. It takes a lot of time and patience but I was bored with the same designs. I managed to tattoo my Sims eyelids under their eyes and was so proud of myself! 

As a console player I agree it's a bit trickier to add things like hills with the landscape tool. I tend to use the softer setting or I find that it runs away a bit and I end up with things in weird sizes and craggy points sticking out of the ground. Plus, hitting the undo button can mean that the next time I load the game my terrain paint has been removed. So that's frustrating. It also works better on a 64x64 lot in my experience. I also use a lot of the move objects cheat (which can be used on console without affecting console trophies and achievements)  bb.moveobjects on to place foliage and rocks around to cover up imperfections in my hilly terrain. So that hill looks great but don't lift up those plants and see the mess underneath!