Tiger Roll has already won a Nash of course, so not sure that's wholly relevant, DO.
Certainly 6/1 is short enough given your destiny isn't always in your own hands, but he has by far and away the best credentials of any runner in the race. And I don't reckon a 9lb higher mark this year is necessarily going to stop him, as he looks like he's improved by more than that in the interim anyway.
Very hard to get away from for Aintree, imo.
He would, however, be a complete no-hoper in a Gold Cup, and 10/1 is a joke price.