Correct me if I'm wrong but so far, it's not possible to edit text already set on a layer which means the first shot must be the right one.
Since I believe it's a very basic function average users need and I haven't found the Krita roadmap, I'd like to know if someone knows when it might be added to Krita features.
No, unfortunately this is not possible. The text turns into a bitmap and you can't edit it easily, only with painting skills. You could file a wish report at http://bugs.kde.org for this.
I searched for a good half hour trying to figure out how to edit some text. So I went back to Gimp and will stay with Gimp until this feature is added.
please vote for this here. they're saying it's resolved because you can somehow do it using an embedded kword, but really this is needed functionality - whatever the default text made needs to be editable! http://bugs.kde.org/votes.cgi?action=show_bug&bug_id=124850