It was a good idea to redo Mahabharath after the super success and classic Mahabharath in the late 1980s. The new generation probably has seen the older one and therefore it is that essential that the audience get connected to the respective characters and audience can visualize indeed this is how those characters could have been as it was with the case with BR Chopra Mahabarath.
Some of the characters are quite iconic in stature be it Bheesm, Karn, Arjun, Duriyodhan, Bheem, or Krishna. They are epitome of Mahabharath and thereby needs really convincing and great actors.