From what I recall Dhoni didn't get out that way at all. He regularly poked outside the offstump edging to Prior and co and left one from Anderson that came in and took the offstump. They were all very poor shots but by no means slogs, and neither was he trying to go hard at the English bowlers to hit his way into form.
In fact the only time he did go aggressive was in the 3rd test where he actually batted well and scored two fifties.
That does not disprove the point that it is not lack of concentration but lack of ability.
Poking outside the offstump is the common issue with players who lack good defense, most often backfoot defense. A prime example is Mr Gautam Gambhir. He always suffered this deficiency (still does) and is not able to negotiate the in-between length delivery just outside the off stump which he cant slash to point without looking unfit to open the innings if he keeps getting out that way and cant go back on to his stumps and defend with a straight bat or leave alone. So Mr Gambhir pokes at it in a nervous reactive manner. The only big surprise to his troubles because of that is how long his deficiency in having no back foot defense (disastrous in an opener) went un-noticed by the bowlers in the world for so long..
Gambhir also tried the method of jumping out to the quicker bowlers to make them pitch short so that he could get the width and the length he needed to play the cut but it can't work if the bowlers just keep bowling it there and it finally caught up with him.
The fact that Dhoni poked at them and got out while his attempts to slog sometimes resulted in a few quick runs does not change anything about the point I was making.
A lot of people have been talking of Dhoni's reinventing himself as a batsman because of his dropping strike rate. This is true. But the reason is not a sense of responsibility alone. Dhoni is the smartest cricketer in India (and I include Sachin here) and he realises his deficiencies as much as the best of them (again I include Sachin who sometimes fails to do so) and Dhoni realised his game, rustic street cricketer that he played like) was not good enough against the best in testing conditions and most of all in the longer version of the game. He realised too that it was too late for him to go back to the drawing board and change/work-on his technique in any significant way. So he decided to use his do-it-yourself coaching. Slowly and surely he has been working on how to make the best use of his power and great hands and how to minimise the drawbacks that his woeful technique brings.
This is Dhoni's great self drawn new portrait of himself. He is not going to become a champion batsman in trying conditions. He is still going to look less than very good when the ball moves laterally, late and enough. I am sure he realises that but this does not deter him from getting the best out of himself. For this I salute him and am a great admirer. However, this does not make me tag him with qualities he does not have for they do not necessarily strengthen his case as a remarkable self-made cricketer who is a law unto himself.
Dhoni is technically deficient - PERIOD.
Dhoni refuses to let his deficiencies deter him - FACT
Dhoni has been trying different ways to overcome the situations which have troubled him and had limited success in the longer version and in trying conditions - FACT
He is still working at it and is possibly going to emerge a better if imperfect batsman - MOST LIKELY
I consider Dhoni as among the three best Indian captains that I have seen along with Pataudi and Ganguly. All three had different strengths with the Nawab being the most rounded. Dhoni joins that list because he is the most committed and the most responsible of all Indian captains one has seen in the last half a century and not concentrating when playing for his country would never ever be even a blip in Dhoni's thoughts.
There are others who when faced with difficult situations/form have tried to hit their way out in the correct team - Sehwag is the prime example and the one I am hinting at but unlike Dhoni, Sehwag, when he finds his methods are not working hasn't shown the tendency to do something different (although he may just be starting to do that). Dhoni does not think let alone say things like "This is the way I play and this is what you get from me" Thats why, inspite of being a very good tactical captain, Sehwag should never replace Dhoni as captain as long as MSD is available. For he is a man who does what HE THINKS the team needs. We may disagree with him as most people do in his choice of Jadeja but then that will alwayd happen when a you have a strong man at the helm and Dhoni is nothing if not a strong man - mentally much more than his obvious physical strength.
No I am not digressing or blabbering. The point is that everything about Dhoni is about responsibility and doing his utmost for the team's cause. To suggest that such a man did not concentrate in an entire series, even if one is trying to explain away a heroes technical deficiencies, is to do great injustice to him.