I don't think you're going to see a sudden change in the tactical approach just the formation one.
The whole point of the press and possession based football is to literally tire/exhaust the opposition. As players/teams tire structural and tatical discipline decays and gaps open.
There is nothing more tiring than chasing ghosts and not seeing the ball, the strategic thinking behind it originally was that in South America they had to find away to counter the predominately defensive nature of games by less capable/less technical teams; then as the game wears on youcould adjust intelligently to the opposition formation/tactics/game management - It's been proven many times over that tiring teams lose both mental and physical concentration under these circumstances - basically that's the speech Poch made in explanation of the system that we employ and why he puts so much credence on physical fitness, tacticalawareness/footballing intelligence and that judgement starts by what he sees on the training pitch and in the tactical classroom based sessions.
So I expect formation changes, but the 'system' to largely remain intact whereby we try and conserve energy whilst they tire - it's why you often see 'press' periods and then periods of recovery rather than constant press at 100 mph.
The trouble comes when you come up against a better technical team and simply put, better more creative players - and city have them in abundance.
There isn't one of their 'b' team that wouldn't get into our squad in a walk, that in itself is hugely intimidating when you're trying to come up with a winning strategy.