Interesting days; as we reconsider, with a glorious new open-mindedness, rules laid down in the post-Conciliar period, and customs that have grown up since then, we find ourselves reviewing what, for more than a generation, we have taken for granted.
Who should do the Intercession? The Pauline Rite says that the 'priest' is in charge (moderari); that he invites the Faithful to pray; that he concludes it with a collect (oratione). But it is suitable (expedit) for the 'intentiones' to be done by the Deacon, a cantor, 'vel ab alio'. It has been the custom in televised papal liturgies for a variety of laypeople in a variety of langages to give the intentions. Common Worship cheerfully regards 'leading the prayers of intercession' as part of 'The ministry of the members of the congregation'.
In the earlier Roman Rite, the Solemn Prayers (surviving on Good Friday) were done by the Deacon giving the people an intention; after a silence the Pontiff sang a collect. The Deprecatio papae Gelasii divided the giving of the Intentions between Deacon and Schola - and the people responded Kyrie eleison. But at one stage it appears that within the Eucharistic Prayer the deacon read the Memento and Memento etiam. In the Byzantine Rite the Deacon proclaims the Intentions and the people reply with Kyrie eleison.
I would be interested to know what conclusions others would daw from this or from other evidence. It seems to me that the practice, common among modern Anglicans, of leaving the Intercession to some lay person both to write and to deliver and allowing it to be done in some less than formal place within the church, receives little support from ancient precedent or from modern Roman legislation. The celebrant should be in charge and the the rite should not be regarded as a moment of informality in the Mass: as though we heave a sigh of relief and thank God for giving us a few moments of freedom in which we are not dominated by hieratic ministers and hieratic ritual. The Intercession should be conspicuously part of the official worship of the Church.
My own reading of the Tradition suggests to me that it should have a formal shape and wording and be integrated into the ritual activity of Priest or Deacon or Schola or Reader.