The genius for story-telling is just the genius which is incapable of being a fine dramatist.

And the opposite is also true.

Shakespeare, great as his genius was, would not have been able to write a single one of the Canterbury Tales.

He would have been driven into dramatising them.
Neither Tennyson nor Browning had dramatic genius--that is, the power to conceive, build, co-ordinate and finish a drama.

But they thought they had, and we may pardon them for trying their hand.