Since I'm going to be a bit slow today, I recommend this incisive post
by Steven Greydanus at Defensor Fidei on Catholicism and Eastern Orthodoxy. He has a good summary to the so-called 'Goldilocks Approach' of many Orthodox; he focuses on the historical insight (often made by Newman) that heresy always represents a negation from the truth, Catholicism the fullness of it:
". . . [T]he long history of heresy, schism, and religious error offers an embarrassment of riches of evidence of a frighteningly consistent dynamic in one specific direction. The "too little" error is overwhelmingly the error of choice of the heretic and schismatic, if indeed the "too much" error has EVER been committed.
Indeed, the history of heresy could persuasively be characterized as a history of all the different "too-little" options one can possibly take -- all the ways that divine truth can be split up, with one truth set in false opposition to another truth, and one affirmed and the other denied. Divine truth is so large and mysterious, and our finite minds can understand so little of how it all fits together, that the temptation to fixate on one element of it to the exclusion of others is almost irresistible."