One thing I really liked about the old TF2 Classic menu is that it was easy to just join a server in a single click. Currently, you need to click to get inside the server browser and then click again to join the server you want. It's a minor thing, but it's always nice when the user experience can flow with as few clicks as possible.
I get why this was removed, as I imagine the devs wouldn't want everyone to just join the servers that were on the main menu and leave all the other server networks to rot like the live TF2 community servers tab. However, I wonder if there could be a compromise with this tab showing up once the player starts favoriting servers, like so