Portal chambers
Naked teleporting network - very limited in options (max 6 chambers around the world).
"Yadayada, local banking, etc. etc." - it doesn't work. Either do linked markets like Raap suggested, or allow for naked teleporting. You can already do it through deathjumping pretty much, so why not make it an equal feature for everyone, and not just those with extensive holding and housing networks currently.
You'd still have to move items manually to fill banks around the world. Running around for 1h+ to find pvp isn't fun, it will never be. The population won't pick up if elementary convenience issues like this exists; nobody wants to WORK in a game. It doesn't have to be like ROA, and it can still keep local banking intact. The very hardcore format of local banking in DND right now with limited supplementary features to make it meaningful is killing the game. It's killed off so many clans this "tedium", and to what end? What is the resulting gain from this tedium? Do we have more immersion? More unique players with specialized crafting and trading routes?
Naked porting already exists, open it up for everyone. Make it very selective, and expensive. I bet you there would be a huge population spike from such a compromise.