Well, it is fairly impactful in that if the automatic stair generation puts a down stair where an up/down stair should have been, there is no way to completely fix it. You can build the correct stairs, but it will never be carved out of natural rock since that rock has been removed. Call me crazy, but that's a distinction that matters to me in what is effectively a procedural story generator.

More generally, it speaks to a level of sloppiness that tells me I'm better off waiting a couple of years. I've played a lot of buggy DF builds over the years. It's just part of the experience, but I don't have as much free times as I used to so I'd rather wait than play through the bugs these days.

Oh that wasnt clear to me, that makes sense, thank you!

There are stairs that only go up or down?...

Yes. Lets see if I can make an ASCII rendition that renders correctly. `-` is level floor, `v` is a down stair, `x` is an up/down stair and `^` is an up stair. The simplest possible stair connection between layers is a down stair above with an up stair below:

    ---v---
    ---^---

To make a very tall staircase, you can either stack pairs of stairs next to each other (this approach actually has some gameplay benefits, but isn't usually necessary):

    ---v-----
    ---^v----
    ----^v---
    -----^---

Or, you can use up/down stairs, which are a single block that acts as both an up and a down stair:

    ---v---
    ---x---
    ---x---
    ---^---

In the ASCII game, you had to place all of these manually, so you were in full control. In the new Steam game, it's my understanding that you just select the top and bottom layers for your staircase and it automatically builds the "right" stair types for you. The problem I have seen reported is that sometimes it will erroneously designate something like this:

    ---v---
    ---v---
    ---x---
    ---^---

This staircase does not allow dwarves to transit from layer 2 up to layer 1, and permanently removes material, meaning it's not possible to completely fix the mistake.

You can always construct stairs, so it's not permanent. The stairs really are a lot less complicated now, IMO

Call me crazy if you want, but a mistake that leads to having to add a constructed tile to what should have been a purely carved room is borderline grounds for abandoning a fort in my book.

Well, it was equally possible to make mistakes with the old system...

Haven't seen that bug happen so far. Wonder if it's just a case where someone had already mined out one of the tiles that should have been an up/down, so all the game could do is put a down stair. That said, I only really use stairs for exploration or project tunnels, and it's all ramps in my fortress proper.

I did notice that it seems like dwarves won't/can't dig straight up with stairs, they need another path up. Not sure if that's new or pre-existing limitation, as I haven't played classic in over a decade.

Ah I see, that makes sense to build stairs in a shape of, huh, stairs. Thanks for that explanation :)

Relative to a particular floor, there are stairs that go up to the floor above and there are stairs that go down to the floor below.