That is an interesting question.
I am rather inclined to do the engineering for this in my provisional parser, though I might try to maintain it in such a way that I can set it either way.
("This" being to restrict PO, PU ZO to long scope and make them construct long-scope predicates,
leaving in the short scope operators POI PUU ZOO that I have installed already in my provisional parser. This would also require text changes: any occurrence of short scope PO would need to be replaced with POI -- the other operators occur more rarely. The terminator GUO would then close PO/PU/ZO predicates rather than LEPO descriptions -- it would still close these descriptions because they would be reparsed as including such predicates (there would no longer need to be a LEPO word class)).
I am hesitant about this because changes that actually require multiple changes in the corpus of existing text should always be approached with caution. There are cases where I have done this, where I regard existing solutions as unsatisfactory:
the elimination of unmarked vocatives (Keugru approved already) and other
changes to serial names generally.
complete change of strong quotation (as yet not discussed much)
acronyms (I have fiddled with these extensively; they were causing pain to the previous
Keugru, and recently this has been discussed)
There are other changes to the grammar which I have made quite happily because they are reasonable and do not actually affect any existing text (or only slightly).
I haven't been inclined to "fix" LE,PO because it struck me that occurrences of this exact problem were quite rare and perhaps exactly because it is a historical issue with the Lojbanists. But the problem Peter points out is a further difficulty with the short scope/long scope distinction which is to my mind quite ugly (it is really nasty to have a family of predicates which cannot appear in metaphors for no clear reason) and which has a solution which is arbitrary seeming because it is actually purely an accident.
If I decide to so this, I will enter an official Proposal that we make the indicated change.
Whatever considerations of style led the founders to make the short-scope/long-scope decision would still be supported by the presence of the short-scope words as an alternative. This would also make repairing old text easier.
Answering Peter's question directly, looking at the NB3 corpus I see a number of examples where POI would need to replace PO. Most occurrences of PO are long scope in descriptions. Most predicate occurrences of PO are applied to single words, which suggests reasons why TLI made the earlier decision. I would rather replace PO SUCMI (short scope) with POI SUCMI than with
PO SUCMI GUO, on the whole.
Opinions from other members of la Keugru?