I do realise that there are a few posts asking for these things partially or completely - such as this and this. One of the reasons for introducing the left sidebar was that Teams could be accessed there, and with the current changes - we'll be losing that.
This seems a good time as any to ask if we could have chat and meta added to the side bar. I'd almost say reinstated, since in the old days we had it in the top bar. Maybe add a link to meta (that turns to 'main' while using meta) and chat.
For that matter, a new user won't know that the help is on the question mark symbol on top. Adding that as well, and turning the left sidebar as the 'home' for all local/site related activities sounds like a even better idea.
There's no longer going to be private Q&A on the side bar (network wide), and it feels like a good time to consider bringing these parts of our site home, rather than put them in the attic where no one can really find them.