Joseph Cardinal Ratzinger made a strong case for this:
This is, of course, a misunderstanding of the significance of the Roman basilica and of the positioning of its altar, and the representation of the Last Supper is also, to say the least, inaccurate. Consider, for example, what Louis Bouyer has to say on the subject:
The idea that celebration versus populum was the original form, indeed the way the Last Supper itself was celebrated, rests purely and simply on a mistaken idea of what a banquet, Christian or even non-Christian, was like in antiquity. In the earliest days of Christianity the head of table never took his place facing the other participants. Everyone sat or lay on the convex side of an S-shaped or horseshoe-shaped table. Nowhere in Christian antiquity could anyone have come up with the idea that the man presiding at the meal had to take his place versus populum. The communal character of a meal was emphasized by precisely the opposite arrangement, namely, by the fact that everyone at the meal found himself on the same side of the table (54f).
…Once again let me quote Bouyer:
Never and nowhere before (that is, before the sixteenth century) is there any indication of the slightest importance being attached, or even attention given, to the question of whether the priest should celebrate with the people behind him or in front of him. Professor Cyril Vogel has proved that, “if anything was stressed, it was that the priest should recite the Eucharistic Prayer, like all other prayers, turned towards the East Even when the orientation of the church allowed the priest to pray facing the people, we must not forget that it was not just the priest who turned to the East, but the whole congregation with him” (p. 56).
He also observes that:
Turn to the East is essential
On the other hand, a common turning to the East during the Eucharistic Prayer remains essential. This is not a case of accidentals, but of essentials. Looking at the priest has no importance. What matters is looking together at the Lord. It is not now a question of dialogue, but of common worship, of setting off towards the One who is to come. What corresponds with the reality of what is happening is not the closed circle, but the common movement forward expressed in a common direction for prayer…
… see a solution to this in a suggestion I noted at the beginning in connection with the insights of Erik Peterson. Facing toward the East, as we heard, was linked with the “sign of the Son of Man”, with the Cross, which announces Our Lord’s Second Coming. That is why, very early on, the East was linked with the sign of the cross. Where a direct common turning toward the East is not possible, the cross can serve as the interior “East” of faith. It should stand in the middle of the altar and be the common point of focus for both priest and praying community.
In this way we obey the ancient call to prayer: Conversi ad Dominum, “Turn to the Lord!” In this way we look together at the One whose Death tore the veil of the Temple – the One who stands before the Father for us and encloses us in His arms in order to make us the new and living Temple.
This comes from “The Spirit of the Liturgy”. The Holy Father certainly practices what he preaches.