...I really just want more aspirations, playable careers and events. I think I've made many posts about how each pack could have at least 1 of those added that I'd really like, and a lot of those ideas have already been mentioned here (slumber parties, pool parties, paparazzi career, vampire hunter career and/or aspiration). Trying to put those aside tho...
Get To Work: A type of lot that allows your sim to live in their shop as their full time residence, without needing to buy two lots.
Get Together: Put something cool in the hedge maze at Von Haunt estate for our sims to discover! Gnomes! Treasure! Curses and blessings like in the Selvadoran Jungle! Just something to make it actually worth wandering in!
City Living: This might be too tall an order, but I'd really like it if the apartment buildings actually had multiple floors for sims to live on? It's so weird to me that you take that elevator ALLLLL the way up, past all those apparently empty floors, to the 2-4 apartments at the top. Adding more livable floors would add more lots to play in, and also just make it feel more like "City Living."
Cats and Dogs: (I actually really like your dog show idea, especially if it came with a "pet training" aspiration BUT ANYWAY) Vaccines! You can pay to get your pet a vaccine that means it won't get sick at all!
Seasons: A "look up forecast" interaction that lets you see the weather in other worlds. It might be a sunny autumn day in Oasis Springs, but if it's storming in Brindleton Bay it might be nice to know that before taking a trip with the dog and kids to the park there.
Get Famous: (Bodyguard idea is great, I'd also had that thought lol) this might be more like a fix-it patch, but I'd really like the ability to designate how probable celebrities showing is at different places. Like, maybe each public lot could have "star meter" that the player could set, with a higher rating increasing the chance for more higher level celebrities. Then, if a player wanted lots of celebrities wandering around they could set all the star ratings high, and if they wanted none they could set them at zero, and then if they (like me) want different lots to be more popular with celebrities than others they could do that too. (Honestly, what I'd really like is for celebrities to basically ONLY show up at places with the hotspot traits, with only VERY VERY rare sightings elsewhere, but that really feels just purely a fic-it and not a new feature, so yeah)
Island living: A tracked swim skill, now separate from fitness, that children can learn after maxing motor.
Discover University: Something that lets you connect/interact with other students taking your sim's same specific classes and major. Maybe a "study group" type thing? But that specifically tells you which sims are in your class? Maybe an "invite classmates over to study" function like the "invite director and co-stars" thing in GF?