We open new servers based on usage and demand. We can't just stop opening new servers until every bug is fixed. Bug fixes are an ongoing process in every game, and each time we add a feature or make a change, there is a fresh round of bugs to fix.

There are no bug-free MMOs. A bug free game is a boring stagnant affair, because any time there is progress, there is the risk of error and of unforeseen consequences.

That said, some of the things listed in this thread as "bugs" (such as the medal drop rate) are not bugs at all, but the intended function of the game.