Personaly I haven't encountered any problems with controls reated with untis and their manouvering. And yes, units keep formations this time.

I've even played a 4v4 match without any lag, but the hoster had around 1MB/s.

Yes, the biggest issues is and remains replay desync but all rest seems ok. I've as well heard that after you install BI, you should re-install it and you will
hardly have any lag, except maybe in 4v4.

When you will be looking for good matches, they are able to be find in chat lobby from 6pm or 7pm GMT on. This is quit same like it was/is in VI lobbies.