For the updates you first listed, you forgot a few things that came to my mind:
We can copy/paste rooms! (Real helpful for multiple beds or baths, for example.)
We can shrink items now, as well as enlarge them! (Helpful for the... larger than life items, lol.)
I mean, I get where you're coming from. I want more stair options for sure. (That's honestly about the most from your list I care about, though a 'water paint' tool similar to the terrain paint tool would be nice too.) But there are a lot of aspects to building in this game that are very nice to have that get overlooked.
You can build a room, for example, then paint it up and fill it with stuff, and if after you're done, you want it bigger, you can just pull on the sides, and bam! Not only is it bigger, but the paint continues on the new wall portions, same with floor coverings. You don't have to delete and re-do wall segments. You can pick up and move entire rooms, even the entire lot, around with a couple clicks of the mouse.
I dunno, it seems much more intuitive and easy to build, and much more difficult to truly mess things up in the process. It's more efficient. Being able to copy entire rooms is a huge time saver. Try making an apartment building, or a nursing home for elderly, lol. And for whatever 'restrictions' there are, well, I've seen plenty of builders get creative and challenged to work around them.
I think the pros outweigh most of the cons. There are a few uses for changing the terrain that I could use, but I also like the fact that any lot I go to build on is also fully open to build on from the start. I don't have to flatten down hills or fill up holes in the ground before laying the first wall down. I can just get right to it.
