The President of the European Council shall, at his level and in that capacity, ensure the external representation of the Union on issues concerning its common foreign and security policy, without prejudice to the powers of the High Representative of the Union for Foreign Affairs and Security Policy.

How can the President of the Council represent the EU abroad if he doesn't have a policy portfolio and if external affairs is essentially the responsibility of the High Representative of the Union for Foreign Affairs and Security Policy?  This seems a recipe for role conflict - as has already begun:
European Tribune - The bigger picture

Now, Blair as president of the Council would want to usurp these attributions of the HRCFSP. That is what the whole Blair row is all about. A move of foreign relations from the Commission towards the Council, to a position somewhat in the middle of the two.

In fact the President of the European Council role seems to be little more than Secretary General of the Council which is half the job Solana currently holds.

So what's all the fuss about?  The actual job spec. is half of Solana's job plus a largely titular role to represent the EU abroad like a formal head of State with no policy or executive functions.

Why would Blair even want that job?

And what is the point of him saying he wants control of trade, foreign policy etc. if that is explicitly not in the Treaty definition of the President of the Council role?

There is something funny going on here - all does not quite seem to be what it seems.  The Secretary General of the Council role seems to be a kind of fixer role for a good negotiator - someone like Bertie Ahern - but not really a prestigious or leadership role as neither the Commission nor the Foreign Policy Chief is under his/her control.

It makes sense to create such a post because rotating the "President of the Council" role between 27 heads of Government every 6 months is clearly unworkable in terms of continuity and suitability, and all the Heads of Govt. have much more important and busy jobs to do heading up their own Governments.  

But the job as defined seems to be all responsibility and no power - you are responsible for moving the EU forward and yet all the key functions are controlled by the commission, foreign policy chief, Parliament etc.

The Chief of Staff to an American President - a role not even in the US constitution - seems to have a lot more power than this - as he controls most appointments, agendas and access to a President who has real power.

I can't see how this is going to work long term - what is the plan for when the inevitable failure occurs - a directly elected President of the Council?

"It's a mystery to me - the game commences, For the usual fee - plus expenses, Confidential information - it's in my diary..."