Dal Santo criticised Shiel for his poor disposal efficiency and inability to consistently hit the scoreboard on SEN Summer Breakfast.
The ex-Giant averaged 26 disposals in his first season at the Bombers but went at just 66 per cent efficiency and booted nine goals from his 22 matches.
Dal Santo believes Shiel must work on those areas of his game to be considered an elite player of the competition.
“I’ve got him a rung down (from elite) at the moment,” he said
“The only reason, I just want to see him tidy up (his disposal). That’s my take.
“If he works on it, he is right in the conversation about being one of the most damaging midfielders with his leg speed, the amount of football that he gets, all of it.
“Kick goals, use it a little better, but can he do it?”
“I saw him running around Dendy Park, Brighton last weekend with no top on. If you could win Brownlows and premierships by the way that you look, he is an all-time great.”
Shiel was traded from GWS to Essendon at the end of the 2017 season for two first-round picks.