I agree with much of your comment, except for the guitar Mass, which I find to be an abomination, but that's my taste.  I agree that most of the liturgical music since the Council has been trite and silly - as if one were singing the praises of Coca-Cola, not God the Father, Son and Spirit.  I also find the "Four Hymn" framework tiresome.  The Roman Missal, if followed properly, has an entrance antiphon, communion antiphon, sung Gloria, Psalm, Eucharistic Antiphons...quite a bit of sung prayer in the Mass, if it were simply celebrated properly.  And, the idea that every spare second of the Mass just has to be filled up with music is ridiculous - sacred silence is nearly nonexistent in our liturgies now, yet God speaks, most often, in the silence, and in our day and age, silence is something most people never experience, yet at the same time, desperately need.