The --available function only pertains to current and previous available flash 11 versions, which would help older hardware none at all, and I don't see a reason not to stay with the latest minor version of the major version being used. But some folks seemed to like to be able to choose a point release in the current flash release cycle. But unless there is a general demand for that in the scm area, it will stay simple.
Using older flash10 or flash9 would help older hardware but would not be compatible with the current web, as far as I know. So that exercise is left to the user.