There are many factors put into where and when a game's release order is. Pokemon games are first developed for the Japanese audience, while some franchises that do well in Western audiences (Metroid series for example) gets localization pushed out really fast. Sometimes a game is also really easy to localize, and it's easier to print and push a certain quantity of discs in certain regions at different times. The backlash isn't major but fans appreciate universal releases, the problem is it takes a bit more money, logistics, delays, or all three to achieve this.