(Warning: this is going to be very long :/ Please excuse typos and such.)
My ideal Sims 5 game would take the best features from the series and expand on them. It's a long list. But, IMO, it's not unreasonable.
- I would like open worlds (or, at the very least, open neighborhoods of no less than ten lots).
- I would like to see CAS and build modes as robust as TS4's along with the CFE cheat from TS2 and TS3 and terrain manipulation as base game features.
- The developers need to leave some of the world-building to the players. In other words, official worlds should be generic enough that players can turn them into anything that they desire. That includes providing the option to customize areas that are off lot! I want the devs to go easy on all of those backgrounds and fake buildings that serve no purpose. In fact, don't use them at all unless the background is way off in the distance, as in TS3. If the team has to create fake buildings the buildings should serve a purpose other than as aesthetic fillers.
- While designing the game, the engineers/devs should make plans for an eventual CAW and player-created worlds. Players don't have the same budget and technical constraints as the design team has. So allow the talented creators in the community to do what they do best!
- The game needs more than one urban world. IRL, many people in the world live in cities. Not everyone can identify with TS4's version of idyllic suburban bliss. Which brings me to: the game should allow players to customize lot sizes and location. As well, lots should be allowed to touch so that players can create row houses and storefronts.
- Along the same vein, players should be allowed to build to the edge of lots again -- walls, and fences.
- All worlds should be residential with the option to temporarily rent a lot or to stay in a hotel. Second homes would be awesome, too.
- Hopefully, TS5 will have worlds that are representative of a broader swath of countries and cultures.
- TS5 shouldn't tell players how to build venues. Allow the players to choose what they want on a lot, not the game engine. Allow Sims to use objects based on traits, not the type of venue.
- Players should be allowed to build apartments and to see immediate neighbors without a loading screen.
- I would love, love, LOVE to see neighbors do all kinds of things. Children should be outside playing tag, hopscotch, tossing frisbees, etc. If there's a clothesline in the yard, I'd like to see the neighbors putting the clothes out or taking them down, that sort of thing. It's time to move beyond neighbors who simply walk past the house.
- There needs to be consistency in the game. All Sims need schedules. Children who aren't in school during school hours should be treated as truants who need to evade adults. And they certainly don't belong up in the club. If my Sim is speaking to someone on the phone, the other Sim should be on the phone, too.
- I need customization for CAS items such as hair and skin tone. Furnishings should have separate swatches for the upholstered parts.
- CAS should allow for more relationships such as in-laws and stepchildren/parents. Extended and blended families are commonplace. That should be reflected in the game.
- I would love TS2's personality system, including wants/fears and favorites in the base game.
- It's time to have an attraction system in the base game.
- There should be more housekeeping chores because the maid in TS4 is practically useless and slobs need more ways to illustrate their sloppiness. Belching and farting don't do it for me.
- There should be cloudy and rainy days in the base game.
- Every single life stage should be represented and fully fleshed out from the beginning. It should be entertaining to play every life stage from toddler to senior. If TS2 could do it, every game in the series should be designed to provide the same.
- There needs to be more recognition of family connections, including a tag that allows the player to see all members of an extended family at once. If we can see all of our Sims' friends, we should be able to see family members as well and for the Sims to acknowledge them as family. I haven't seen this feature since TS2, however, it was integral to my kind of gameplay.
- I would like to see an optional story progression that keeps NPCs from aging and dying off with no offspring to replace them.
- I would also like to see options to turn off occults in specific saves. I would like to see more options as a whole.
- On a related note, stop bloating the world with game-created NPCs. Allow players to assign roles such as mailperson, maids, babysitters, to existing NPCs and player-created Sims.
- At this point in technological advancement, more than eight family members should be allowed in a household and pets should not be included in that number.
- If there are traits, they should be meaningful, affecting behavior, interactions, and relationships.
- Transportation should be in the base game, public and private, for all ages. Cars, motorcycles, bikes, tricycles, push toys for toddlers, strollers, and wagons to bring along the kiddies. I would like to see it all.
- It's also time for an optional summer vacation for the kids and more playground equipment. The stuff that came with TS4 is wholly inadequate. Bigger doesn't mean better.
- Speaking of bigger, I would like the designers to stop creating unnecessarily large objects. Never do it again. Please!
- I would love to see more arcade machines so that players can build arcades for teens and YAs. I would like to see more activities for teens, period. Lan parties, Sims versions of D&D sessions, board games, card games, skateboarding, etc. Trading cards would be cool.
- I would like to see more pool activities. Pools are useful for more than swimming. There can be pool games, pool toys, floats, slides, even water aerobics for the health-conscious. I'd like to see diving boards make a comeback. As well, it would be nice to see Sims diving or jumping into the pool from off the sides.
- If the design team decides to pick a theme, I would like them to go all out like they used to. The devs/EA need to stop trying to stuff large themes into things like stuff packs.
- I would like TS5 to be the end of the practice of squashing themes into packs that aren't big enough to do them justice. I would like TS5 to go back to great expansion packs that fleshed out a single theme and provided for years of replayability.
- I would like cross-pack integration and compatibility to be a priority again.
That's the stuff off the top of my head. I'm sure that I could think of so much more. Yet, more than anything, I need TS5 to be an engrossing
single-player experience that puts an emphasis on fun gameplay and player choice above everything else. Otherwise, the Sims series will come to an end for me. I would honestly hate such an incredible series to end on TS4, a game which, IMO, never lived up to the quality of its predecessors.