In Impress, Insert Slide number inserts too large text box of 10,65 cm.
Insert Slide Count is just 1,27 cm.
Both should be able just to accomodate "123".
The command for Insert > Slide Number was switched in 6.2 from .uno:InsertSlideNumber to .uno:InsertSlideField with c50e4badfcb701d9e3927dae6617bb0d33f386e0
But the field was always available with Insert > Fields > Slide Number, and was the same size in OOo 3.3 -> inherited.
I agree it's a bug, all other fields have a size just sufficient to fit the contents.
Hossein, an easyHack?