I think if you manage it properly there is always room for a "flawed genius" in any team. However, I think there are, his book etc aside, two main obstacles to KP getting back in the test team. Firstly, England are far too reliant upon Anderson & Broad in their attack who were two of the individuals he had major issues with. I can't see England upsetting them when they are so heavily reliant upon them. Secondly, and probably more importantly at the moment there is nowhere for KP to fit back into the team. If you play him it is either as a 3,4 or 5 positions currently held by Ballance, Bell and Root. Currently, Ballance has an average only second to Bradman, Bell has scored 2 100s in his last 5 tests & averaged over 40 last summer, and Root is one of the in form batsmen in world cricket and averages over 55. You can't drop any of them currently.
On the other hand, I think there is a genuine case for him getting back into the ODI and T20 teams. English one day cricket has been gubbed for a long time now and really reached low ebb at the last World Cup. England played a brand of cricket from 5 years ago, 350 is the new 280 and looking to take wickets is now the best form of defence as opposed to containment. It is no coincidence that England have played their best ODI and T20 with KP in the team as he is along with Buttler their most dynamic batsman with the ability to whack it out the park 360 degrees required in the modern game.
The experience he has gained through playing IPL,CPL,Big Bash could prove invaluable in getting England playing some modern one day cricket. There is also the advantage of him being able to bat anywhere between 1-4 in limited overs cricket, which is the area that England really need to address, and offer the high tempo start to the innings required in the modern game. Similarly, the limited overs sides being of a rather different make up to the test side and more youthful, lack any the of the individuals that he fell out with previously, apart from Broad. I know Anderson played in the World Cup but he should be kept as a test specialist now. Therefore, the potential for dressing room upset is greatly reduced, and he can hopefully pass on his knowledge to the young guys in the side. Another added bonus is he is good mates with Eoin Morgan who I reckon could help him curb his 'excesses'.