This modification would work for binary operators, but the problem arises with unary operators. For example * is the binary operator for multiplication, but the unary operator/sigil for globs, so while $a *= 123, can't mistake the = as a bareword, and so *= is matched, $a =* abc (with no strict, so that barewords are allowed), could parse as either $a *= abc, or $a = *abc (although the first doesn't make much sense). This would probably complicate the parser with unnecessary lookaheads, and backtracking to allow it to DWIM between the cases.