Personally, for what my opinion is worth, I think it is a terrible idea, not because projectors are evil, but because it detracts from the realities of Mass, and interrupts the exchange between God and man. There is a significant body of Catholic thinking that points to detachment as an important part of the spiritual life. At some point the sensory output becomes what might be called “inordinate”. I’m not certain where that line is, but it seems to me we are crossing the line.
Vatican 2 calls for full, conscious, and active participation. In what? The sacrifice of the Mass. Projections seem to detract from the active part of that equation. Feeding ourselves by passive video consumption panders to our culture, in which people already expect constant gratification of the senses, to be consuming information constantly in various ways.
We know that excessive video consumption is harmful to children, and adults for that matter. Why is that? And why should this form of consumerism be brought into the Mass?