Is it not normal to have a lot of bathrooms? In an ideal house build, I like to have one bathroom for every sim that will live there. Since that can vary, I try to have a minimum of 4 bathrooms, but can have as many as 6 or more.
My current Legacy house has 5. Three downstairs and 2 upstairs and if I could figure out a way to get a sixth one upstairs, I would.
As far as minimal effort, I'm not blown away by any of the EA houses in game. I definitely see much more talented builders on the gallery. I think they should be hired to build houses for the sims. But, I think what we have it fine for what it is. We do have the gallery for more detailed tastes and desires. Heck, I'm not even a builder and I build in sims 4 and usually end up, pretty much, happy with what I've built. We really do have lots of options, so I can kind of see the devs not spending a ton of time to give us epic houses, though a few really nice EA houses would be nice.
And then, of course, there is the "can't please everyone" business. I'm sure, no matter what they did, someone would complain about something. If they really built amazing builds, someone would prefer Victorian. Or another would want modern. Or another traditional. Someone, somewhere, would complain that their style was being ignored. So, they give us basic houses, basic designs and we can either build our own or find something fitting our style of the gallery.
I get it.