Changes in ritual and discipline surely have altered the "look and feel" of the institutional Church, but these superficial adaptations have no bearing on the ecclesial life-in-Christ that the Church has always offered. To read Augustine or the canon of Hipolytus or even the Didache is to see vivid accounts of substantially the same liturgies the Catholics offer today. The ancient (and even mediaeval) Christians, who were quite familiar with the concept of multiple Western rites, would have no difficulty whatever in perceiving an orthodox Novus Ordo (English) Mass as thoroughly Catholic.
As you say, "it's not worth splitting hairs over." Soothly!