I am just going to copy/paste my respose to the other Multiplayer suggestion thread.
I am not in favor of this added to Sims 4. A spinoff Sims title with multi-player is fine, but I play the Sims franchise because it is a single-player game. They did try that in the early 2000's, it was called the Sims Online. I have been playing games in the franchise since the first game in 2000. I skipped the Sims Online, because I just saw no point to it. I do not have friends that play Sims 4 and my family (my children) that also play the game also enjoys that it is a single-player experience on my profile. Creating the option also would take money away from making a better single-player experience, although Sims 4 was originally supposed to be an online game according to the research, which is why the sims in the game all feel the same and have no distinct personalities.