This is such a great thread! There is so much to love about build mode in Sims 4 and a few little (? maybe not so little - I know nothing about programming) things would make me love it even more. I'd mostly just like to add another 'yes' to the votes of people asking for an official MOO cheat and, if not an image changer, maybe at least an image selector that would give us different angles and distances to choose from for our gallery pic. I mention distance because that would prevent things like this: http://forums.thesims.com/en_US/discussion/comment/12793505/#Comment_12793505 (I'll just post a link rather than re-post those big 'ole pics). Though, even if we had an image selector, I'd still want a UIC from a modder. :)
Also, I read through most of this thread, but I still might have missed it said... I would love the ability to change the color and brightness of light fixtures in build/buy mode.