Submit/Workflow question

Suppose that I have created a half-baked patch A suiting my personal needs and went on from there, having something like

...->A->B->...

Now at some point of time I decide that really A should be made fit for submission. Basically, I'd want to do git-reset --hard A [edit some] git-commit --amend -a git-format-patch HEAD~1

in order to arrive at a nice submittable patch. However, I don't want to lose B and the following stuff, and the resulting HEAD should include the improved of A (it is fine if that needs additional steps, and it is fine if it is just HEAD that gets the fixed version, not B).

So how to do this? Branch at A^, rebase on A, fix the stuff, commit with --amend -a, rebase on master, rename the temporary branch to master (killing the old master), format and submit the patch?

Or is there some bad thinko in there?  Or is this too complicated?