Your bandwidth costs normally far exceed your hosting costs. Hardware is cheap (relatively). Bandwidth is not and most your bandwidth costs are going to depend on gameplay systems (stats, character customization, etc x number of concurrent players). It’s more important, in my opinion, to get something up on screen working as quick as possible so your designers/artists/other programmers can spend time building a fun game. A super tiny server application is pointless in a game that is no fun (or isn’t ever going to launch). Replacing the back end with a leaner executable can be done as you reach the optimization focus of your development cycle. Keeping Design unblocked and working is paramount given the amount of content you need in an average MMO.