It's easy to simplfy it, The fact remains we have lag due to 1.) a ton of connections are hammering the the servers all at the same time. 2.) The code is simply not optimized to handle it all. Adding another server would not fix this, all it would do is further diminish the player base. We don't need a second server for the simple fact we don't have the players to fill the first.
It's not splitting hairs when describing the problem.