pd-l2ork is more recent, so i guess it use all latest vanilla feature.
I think the aim is to be able to create object that are more optimized than native one. Or that add functionalities.
Of course, one can use this feature to completely break pd.
it's possible to develop a [+] object that add number and string.
there is no problem overwriting a vanilla object as long as you keep compatibilities.
So, i don't see any problem overwriting vanilla objects, as long as object developers don't do anything stupid.
anyhow, it make sens to be able to load zexy/<~ or nettles/<~ even if zexy and nettles are loaded as a lib. but [<~] is not vanilla, so this is an other discussion than vanilla object being overwritten.
and for this specific object, what make more sense to me is to use a small abstraction made around tabread~ and a 2 points table.
100% vanilla.
0% trouble.