4th generation v6 215000 miles ,is it worth replacing rear crank seal? mechnic there may be too much play, would not seal, need to know if its worth a try

 

If it is just small drops and not a major oilleak , I would leave it alone.

 

If there is too much play then maybe it needs the thrust bearing replaced. With the transmission out to do the rear seal the bearings can be replaced while the engine is still in the car.
Are you sure it is the main seal? On the 60 degree V6 there may be a bolt on plate with a gasket for the cam instead of a plug. Those gaskets are good for leaking.