Developers are stepping back from BlackBerry because they say creating apps is too complex and costly for the size of the market. RIM’s devices have different screens sizes, varied operating systems and several ways to navigate, from a physical keyboard to touchscreen to a scroll button. In deploying Apple applications, there are very few surprises . . . In Android, there are increasingly more surprises. But in BlackBerry, there are immediately lots of gotchas across the board.