A. First, let me point you to a post I wrote giving a variety of reasons why Mass ought to be celebrated with father and the people facing together towards the Lord that might address some of your concerns. But, to speak directly to the Last Supper issue, I think I'll let Pope Benedict answer this directly:
The idea that a celebration facing the people must have been a primitive one, and that especially of the last supper, has no other foundation than a mistaken view of what a meal could be in antiquity, Christian or not. In no meal of the early Christian era, did the president of the banqueting assembly ever face the other participants. They were all sitting, or reclining, on the convex side of a C-shaped table, or of a table having approximately the shape of a horse shoe. The other side was always left empty for the service. Nowhere in Christian antiquity, could have arisen the idea of having to 'face the people' to preside at a meal. The communal character of a meal was emphasized just by the opposite direction: the fact that all participants were on the same side of the table. (Louis Bouyer as quoted in The Spirit of the Liturgy by Pope Benedict XVI)
|The Last Supper by Tintoretto (Titian)|
Indeed, Pope Benedict goes on to remind us that a meal isn't the essence of the Mass.
In any case, there is a further point that we must add to this discussion of the '"shape" of meals: the Eucharist that Christians celebrate really cannot adequately be described by the term "meal". True, the Lord established the new reality of Christian worship within the framework of a Jewish (Passover) meal, but it was precisely this new reality, not the meal as such, that he commanded us to repeat. Very soon the new reality was separated from its ancient context and found its proper and suitable form, a form already predetermined by the fact that the Eucharist refers back to the Cross and thus to the transformation of the Temple sacrifice into worship of God that is in harmony with logos.... This new and all-encompassing form of worship could not be derived simply from the meal but had to be defined through the interconnection of Temple and synagogue, Word and sacrament, cosmos and history. (The Spirit of the Liturgy)Thus we see that, for Catholics, worship (i.e. the Mass) is much more than "table fellowship." It is the offering of the once for all sacrifice to the Father in the Spirit (the fulfillment of the Temple) of the Word made flesh (the fulfillment of the synagogue).