The claimed authority of the pope is a bigger distinction for one, in my humble opinion...
...Popes come and go, and some are better than others and are so judged by the faithful...the ‘claimed authority’ you deride proceeds from a direct line of apostolic succession that we believe in and cherish...on the other hand, the presence of Jesus Christ in the Eucharist is forever and inviolate, and is the reason for for celebrating the Mass...the symbolism evident in the Protestant communion couldn’t possible constitute a more major distinction....
"Forever and inviolate" LOL. This so reminds me of what I was just reading in jude:16: "and their mouth speaketh great swelling words, having men's persons in admiration because of advantage". The persons in admiration sure reminds me of RC's constant habit of droping the names of "church fathers" and popes as if that trumps scipture.