Why would the map have anything to do with whats balanced?
Players dont value maps the same way. Specific civs likes specific land.
The ONLY possible balance issue regarding maps that I could see, is Small continents, with High water.
Then Norway would have a big advantage.
Or Pangea, then civs who has any power with ocean units, gets weakend.
But thats it......
I think the word "Balance", means differently to people. Balance isnt to get the best for YOUR civ or YOUR view on whats a good terrain.
Balance isnt that everyone starts with the same thing. Like close to a natural wonder, city state, etc.
Each game is up to you! You dont like your starting area? ADAPT, and expand.
Someone got more bonus and lux where they started then others? SO WHAT?!!??!
In MP, I only play with Continents or Fractal. Normal everything, but legendary start = ALL will gets something lux/bonus
Also, spending a few moves exploring IS a choice all can do. Sure, you loose not having a capital, but you increase your chance of putting the capital in the better spot.
This is a choice, you live with.
I always play on Maraton. Because in MP, I play with players I played with before.
When starting a MP game, I always give 5 turns for everyone to say if the map was good, or not. AS IN; if you start in only Snow = you say so, and we create a new map.
Civ is balanced enough. In multiplaying, its the human and pure luck thats the real power.