Melko,
The block is your answer for scaling in one direction.
As for the concern for losing "PLINES" and other "polygons", this should not be a concern at all.
You would have to explode twice (2X) to explode these items.
The 1st "explode" would drop the block property or grouping of items. And a 2nd "explode would drop the "PLINE" thickness or other "polygons" ... which of course you would have to select individually or select ALL at one time.
In either case you would have to "go out of your way" to "Explode" the properties of any "PLINE" and "polygons".
But here are some tips for doing the scaling.
type "block"
PICK a base point that you can see on screen Or a point you wish to HOLD.
then pick the "properties icon" and scale as you see fit.
hope this helps.