Interesting post, good reference for discussion.
However, it could be you're forgetting the actual City we've witnessed during Guardiola's 1st season. In that case, I would suggest you go back and watch matches. You will find plenty of material proving you've misjudged our actual needs. I'm referring to situations where we lose the ball high up, with 3F+2AM plus probably a fullback, out of play, that's 5 or 6 players unable to contribute to defense. Opposition goes quickly on the break, the spaces in midfield are HUGE, Ferna suffers or Yaya gets embarrassed. Also referring to sistuations where Ferna (usually or Yaya rarely) moves forward to kill the play in its beginning, but gets it wrong, loses the battle. Again, HUGE spaces in front of the back four and potentially dangerous situations. And so on...
It doesn't matter if those plays led to clear opportunities / goals, that's down to the way the opposition exploited them, what matters is:
we faced plenty of them,
defensive line was exposed.
However, in the 2nd phrase of your post I've highlighted, you leave room for interesting assumptions, but you need to elaborate on this. I think you are "investing" to the certainty of upgrading certain positions in the squad. I do too, the whole forum does. Strong fullbacks with better defensive skills with "speed of thought", as you say, I agree 100%, an absolute must for a Guardiola defender. People able to make the quickest decisions, take the initiative, move forward to kill the play / intercept, before it develops into a dangerous situation. The thing is, defensive behaviour will not inprove significantly if you do not spend time in the training ground, getting the team (ALL versions of the team: rotation) familiar with all kinds of possible situations the moment we lose the ball: how do we defend as an organised defense, how do we operate when caught on the break with 5 (4+1), or 4 or 3 or 2 players left behind. How do we position ourselves when attacking so that we minimise the risk, like preventing / avoiding dangerous situations when losing the ball, and so on, and so on...
During 1st season the emphasis was put on establishing a certain style, a way of playing. The results regarding this have been highly impressive, as far as I am concerned, personally I haven't seen such an improvement in such a small period of time, it was incredible. On the other hand, prioritizing on the team's behaviour WITH the ball, combined with absolutely wrong decisions in the summer transfer window (problems taken care of as we speak, could have been solved a year ago though), lack of knowledge of the PL realities etc etc etc, led to a clearly imballanced team. Which in turn led to lack of confidence and belief (how can you enter the pitch optimistic knowing that however hard you work, no matter how many goals you score, eventually you will concede and lose / not win matches?). To fix this, you obviously need reinforcements, but that's not enough. It's not that simple, never has been. You need to work consistently on the training ground, teaching your players to defend as a unit to all kinds of possible situations. Otherwise we are bound to suffer again. Keeping possession of the ball does not define a viable defensive strategy, because eventually you will lose the god damn thing...
In any case, you will need pace - acceleration in the player for the position you are talking about. And since we're in the Fabinio thread, let's all have in mind that the guy operated in a 2-CM arrangement in Monaco, he wasn't alone in central midfield, there was Bacayoko beside him. I've been watching Ligue 1, Monaco in particular (as well as other clubs), I know him, he's a great player. Nevertheless Guardiola's football is extremely demanding, therefore you will need tactical awareness, you will need a player who is intelligent, tough, determined, effective and you will definitely need all the fucking pace you can get in that position (plus other attributes as well, some of which are mentioned in your post), take my word for it...
