I'm gonna wait until a day after release to play it, just so I can gauge how many bugs are being shipped with it, to see if it's better to wait for a sale or not.
the preview build that people have been getting has had some minor bugs that i imagine will be fixed prior to release
stuff like this:

other than that there are some things that i hope they tweak a little bit, the biggest thing being that i think they need to make it more obvious when a unit can be promoted since that works differently from civ v now. because promoting a unit now requires movement, you have to choose to promote by using a "promote" button, and the only time it prompts you to promote is with a notification that's frankly easy to miss and won't re-appear. maybe making the promotion button flash or something would be a good idea, cus everyone i've seen play so far has frequently gone a fairly long time not noticing they can promote a unit that they're actively using.
also razing currently works
instantly and you can only do it on the turn you capture the city, which i think is a pretty bad idea. would defo prefer that to stay the same as civ v.
it seems like it's stable from what i've seen in singleplayer, hopefully multiplayer will work leagues better than civ v but i haven't looked at any multiplayer gameplay yet