I always thought it would be fun to make a version that was soluble every time by making the system reveal extra tiles as required to always allow you to continue play without guessing. I personally found the situations where half way through a large game you were forced to guess quite frustrating. Maybe deep down I just don't like minesweeper ;)

Or alternatively one that if you click a tile with the best chance in a unsolvable situation always solves in your favor, adjusting bomb locations as necessary.