Perhaps if you would better describe the play? There should be no angular play (I hope I used the correct word here, english is not my native). If you turn one side of driveshaft (say from the diff side) by 90 degress, the same angle should be turned at the wheel side. Or, to put it other way: if you hold the diff side still, the other part of driveshaft should be fixed as well. If you can move the other side (again I am talking about degrees here!) that the CV joint has developed play and should be replaced. To answer the question directly: I don't think I have ever seen the need to replace the complete driveshaft; CV joint was always the faulty part and only that needed replacing.
If you are reffering to the axial play from the diff side, it is normal and in region of 2-3 cms. That is for allowement of a movement in the suspension. The other part of driveshaft is fixed to the hub and shouldn't move at all in relation to the hub (i.e. wheel).
I hope this anwers your question?