An option to have a hub instead of a menu, where you can build your menu basically.
Iirc there was an addon for pre-v21 that did that but because of how it was made it can no longer load on v21.
Basically if you wanted to you could build and create a floating islans hub where each island opens a different menu like the server menu.
And how about if the loading screen/server browser had a server preview uploaded by the owner, along with a description.
And a dual boot option popup before starting blockland giving you a choice between V21 (Modern Blockland) and V20 (Blockland Legacy).
An option to select your own master server ingame for futureproofing.
The ability for users to make their own body part models I.E. more hats. And for client to client DLing of parts, decals and other avatar based add-ons.