Wallin has one good win against Gassiev and a solid showing against Fury. He would not be in Joshua's top 3 wins for me. Klitschko, Povetkin, and Parker are better. Ruiz came in in terrible shape, Pulev was never that good, and Takam isn't an elite heavyweight. I would rank a win over Wallin similar to Joshua's win against Whyte, a solid showing.