Cricket has always been a reasonably specialised sport. You are either a batsman or a bowler or a wicketkeeper or an all-rounder. If you’re a bowler, you’re classified based on your bowling arm and the speed at which you bowl and the spin you impart the ball (last two are not independent). If you’re a batsman you’re classified based on your batting stance and whether you’re an opener or a middle-order batsman.
In Test cricket, there’s further specialisation if you’re a middle-order batsman. You have specialist Number Threes, like Rahul Dravid or Ricky Ponting. You have specialist Number Fours, like Sachin Tendulkar or Younis Khan. Five and six are fungible, but a required ability for both these positions is the ability to bat with the tail.
In One Day cricket, too, there’s some degree of specialisation within the middle order but it’s not to the same extent as in Test Cricket. In One Day cricket, batting orders are more flexible and situation-based. You do have specialist threes (Dravid and Ponting again come to mind) and sixes (usually hitters) but the super-specialisation is not as much as in Test Cricket.
A logical extension of this would be that in T20 cricket, which is played over an even shorter duration and where batting orders are even more flexible, you don’t need even as much of specialisation as in ODIs. However, Siddharth Monga argues in this piece that this lack of specialisation is why India isn’t doing as well as it could in T20s (having just lost the home series to South Africa).
In other words, what Monga is arguing is that Kohli, Raina and Sharma are all similar batsmen and effectively Number Threes for their IPL franchises, and when they are arranged 2-4 or 3-5 in the Indian national team, two of them are effectively batting out of position.
It would be interesting if Monga is indeed right and that T20s require a higher degree of specialisation than ODIs. It is also interesting that India’s number 6, MS Dhoni, bats like a typical number 5 in T20s, accumulating for a while before going bonkers. Maybe T20 will end up as a much more specialised sport than Tests? That would be interesting to watch.