the fact that the drafters of the treaty, (and I spoke to the man who drafted this section of it last week,) envisage that the president of the council's job should ultimately be merged with that of president of the commission.
Who might claim to have actually written the language I don't know, except that it was on the side of the Juncker and small-country camp, and certainly not the A-B-C camp (Aznar-Blair-Chirac). And the Juncker side was/is certainly not in favour of a powerful president of the European Council also taking over the attributions of the Commission president. So I don't know who or what Ivor Roberts is talking about.
Pierre Lequiller, representative of the [French] National Assembly in the Convention, suggested for example a single president of the European Council and of the Commission.