As Pastors and leaders that teach never and I mean never base your calling on how you look, dress and how you deliver your message. To be a biblical teacher is one of the gifts of the Holy Spirit (Ephesians 4:11) and this gift is always from the power of the Holy Spirit and it does not matter how you dress or look or whether you speak well. It will always be if you have the gift of teaching from the Holy Spirit and if God is speaking through you.
Zechariah 4:6 - So he answered and said to me: This is the word of the Lord to Zerubbabel: “Not by might nor by power, but by My Spirit,” Says the Lord of hosts.