Changing filesystem resize patterns

e2fsprogs already has the logic for providing bundles of preset parameters for different usage patterns -- see the '-T' option to mke2fs, and the '[fs_types]' section of mke2fs.conf. The tricky part is in trying to automatically figure out which one is the "right" one to use, which might depend on the nature of the backing device (maybe known at mkfs-time, maybe not if you're just prepping an image to dump to the real device) and on future usage/resizing (much harder to predict, though the backing device might provide some clues to base guesses on).