I can't find the term "special exception" in the OED entry, which treats
than almost correctly, listing it as a "conjuntive particle" (it is actually a conjunction) and "as if it were a preposition" (it is actually just that, a preposition). Why they ever thought using the objective case with
than is exceptional at all is beyond me. However, the errors in the article suffice to bring doubt upon most of what they say if not all.
As I once wrote in the
blog, it is not at all uncommon throughout the world's languages for words to have two function. Prepositions doubling as conjunctions is not uncommon in the least:
for,
but (everyone came but John),
before, are a few in English.
Moreover, bare VERBS also function as prepositions:
save,
except, being the most obvious (there are others).
Keeping in mind my own rule of thumb of consistency, I use the objective case with
than as a preposition and the subjective when it is a conjunction: He is bigger than me but he is bigger than I am. It is simple, it is correct.
I am not denying that verb phrases may be deleted and that "He is bigger than I (am)" is incorrect, only that it is confusing and I am a firm believer that language should promote clarity.