Dominance doesn't really matter unless you win them all.
Their resume of wins look very comparable to me. Martinez was the only national champ that Nolf beat, and then Deakin would win 3 years later. Yianni beat 2x champ Heil (yeah yeah he didn't have a great senior season), and also beat Nick Lee who would go on to be a 2x champ. There are also several guys who Yianni beat that could go on to become champs in future years.
Nolf's other best wins: Kemerer (4-4-3-2), Hidlay (5-4-3-2), Berger (5-3-2), Micah Jordan (6-4-2), Pantaleo (6-5-3), Lavallee (2)
Yianni's other best wins: Meredith (4-2-2), Eierman (5-4-3-2), Sasso (5-2-2), McKenna (3-3-2), Parco (8-6-4 with 2 more years), Lovett (a 2 with 2 more years)