What CAN be done to fix TS4?

+1 to being able to lock doors and gates. It would help to solve some of the issues with npc sims going places, using things and butting into conversations we don't want them to.
+1 make babies independent of their cots PLEASE. It's not getting any less annoying.
+1 doorbells can be added by handy sim
+1 Actually being able to socialise at school/work (and not just in the GTW careers). I also want to bring home co-workers and see who I work with.
+1 vegetarian trait (and eco-friendly)

Bunk beds! Bed/room assignments

Also, generally I'd like to see less focus on "futuristic" and more on "creative" (eg: 1. it's no fun watching sims play video games I'd rather see them create something like sewing, 2. I like old fashioned things like bicycles, kites, etc).

I want the option to choose how many lots are loaded at once so I can load an entire sub-neighbourhood (5 lots is hardly a challenge) to cut down on loading screens. (No open world is probably good, but you took it too far).

Half walls

I'd like to be able to randomize traits for babies, kids, etc outside of CAS as they age up.