I think everyone should calm down a little. This is a very minor issue and one you can configure for yourself.
@mc3man makes a good point that Ubuntu with compiz used smart placement for many years without any complaints. People who are happy tend to not complain.
@jyaku is correct about the initial complaint. But I now realize people might be seeing different smart placement behaviour because of differing screen resolutions…
In a 1080p desktop smart placement will by default put the window in a position such that if you open 2 or 4 of them they will automatically be symmetrically arranged around the center of the desktop. Smart placement seems to be a form of centering . Only after you run out of free desktop space does it use the very top left corner, once, for the 3rd or 5th window only.
In a lower resolution desktop where one window uses more than a quarter of the screen smart placement will put the first window in the top left corner. It’s the same algorithm.
The current statistics on how many users have high or low resolution desktops are here. They are pretty evenly balanced.
Also, I was the one who complained about centred windows. So you can get upset at me instead. If we had a statistically significant set of votes above to the contrary then I would have no argument against centering again. While the stats are even and/or not enough votes, I would tend to support the idea of just using the upstream GNOME defaults. You can also vote for/against changing it upstream here.