I'm obviously not an expert, but waiting for zentara to awake from his oak you can have my humble opinion.

Corion is right: if you have a case where repetition is needed providing some %default is better tan nothing and suffices.

The real problem is that writing a GUI is verbose. My best Tk program is tartaglia's triangle experiment. The interface is clear for my taste but as you can see there are ~70 lines of pure verbose Tk code. Ok I have a lot of -side => 'left',-expand => 1,-padx=>5 but it adds nothing to me if I have some shortcut for this, not even in the Corion's simple way.

Why? Because I generally cut and paste my own code.

Then you can have very sligth differences: nowadays I'm playing with yet another Tk and GD application: look at its init_control_window sub: I'm packing bigger frames with the border and then inside them I put othere smaller frames expanding horizontally, but first and last subframes also need -pady => 5 to look nicer. In the same way if you want something to be packed at -side => 'right' and you want it to not be too much to the border, then the first element (right aligned elements must be packed in reverse order) need a different -padx value. And so on.

So in my humble opinion Tk is already complicated this way and some shortcut as in your example can make it even less redable.

L*