How did you get that situation? It's actually not that easy to do as most methods for re-sizing a layout text object such as your field label won't let you size the object too small. "Too big" on the other hand doesn't really create any major issues for your layout when you view it in browse mode as far as I can tell.
The only way I can get a text object to be a size that doesn't show the whole label is to use the width or height boxes in the inspector.
If I do get layout text that is clipped due to such a re-size, I can snap it back out to the size needed to show the whole text by double clicking the layout text.
You can also select groups of layout text objects by shift clicking or dragging a selection box and then you can resize them all at the same time.
I got into the situation because I've been renaming fields, then renaming the labels then swapping from one font to another …
The main thing that happens is that I make a label and it's say 2cm across, then I rename it with a longer name, and the text jumps down to a second line, then I have to make the field longer and the text goes back onto one line but leaves a second line empty.
So I've lots of text fields with differing amounts of empty field space because of this mucking around.
Yes, your last idea is the one I've been using, it's a long old process though!