The form. I don't remember what it was like in the before-microblog era, but after-microblog it was right below that block header, like this. There was also an intermediate form where it said "X posts" next to "Wall" in the header itself.
And it's also supposed to be collapsible. This is a neat feature.
I'm not quite right referring to it collectively as "old VK design", because it evolved quite a lot between 2010, when the wall gained its microblogging abilities, and 2016, when mail.ru group rolled out the terrible redesign (since redesigned once more and even uglier now). I'm probably going for what it was around 2011.