Rabbi Keleman of Neve Yerushalayim has said about the definition of normal: Hashem, being perfect, is the epitome of normal. The closer one is to Hashem and follows in His ways the more “normal” he is. However, as he deviates from Hashem he is taken further away from the title of “normal”.
Is it actually possible for someone to be totally completely average and not excel at one thing?
Everyone can excel at something. If someone is lacking talents they can make it up by excelling in sensitivity, patience or even talking. Everyone has strengths and weaknesses and I have yet to meet an average person.