We absolutely should not pick a defender with our first round pick, there's too many good forwards at the top of the board to justify doing so.
Patrick, Hischier, Vilardi, Tippett, Pettersson & Mittlestadt are all better picks than any of the defenders.
If we want a defender there's better value to be had in the late 1st / early 2nd round. We would be better served packaging our own 2nd (probably around #35/#36) with some of our surplus picks to move up 10-15 spots and grab the best remaining defender. One or two of Makar, Liljegren, Foote, Valimaki, Heiskanen, Hague & Timmins should still be there. If they aren't then grab another forward in that range (Glass, Suzuki or Yamamoto would be my preferences) and spend the rest of the draft picking defenders in the later rounds.