I think over the full season and at the crucial time when the vote was made yes he was just the better or more influential player as its difficult to compare as they are not like for like.
I think Aguero is one of the very best strikers in the business but in 7 years he has not got near Salahs total, plus the 10 assists he has.
KDB was outstanding til around Jan but since then Silva has outshone him for me so hand on heart I cannot even say he is Citys player of the season (which incidentally I have debated with myself).
If KDB had won it I would not have argued but Salah is also a worthy winner.