I thought of making a poll after reading the argument in the 'This is how Castlevania Judgment should have been' thread. Under normal circumstances, who do you think is the stronger one?
In SotN, Alucard didn't exactly beat Richter; he freed him from Shaft's control. 
In the radio drama, Richter was the one who dealt the critical blow to Magnus, releasing Alucard from his spell. 
However, there's a possibility that Alucard is (as his father says) weakened by his human side, and could be stronger if he's evil.