I think that would be an opinion shared by you alone in this whole world.
In bowling they were probably pretty similar, but in fielding you comparing favourably Sanath, who is a good solid fielder, to Viv who was simply phenomenol in the field. In fact he was a better fielder than he was batsman (and that is saying something). Of all the players I've seen in the field I'd rate Viv only slightly below Roger Harper, and ahead of Symonds.
To think that Santh was a better fielder, betrays you as omeone who never saw the great Viv field. He was a match winner in that capacity alone.