I have a roleplay-based suggestion. As clerics likely would at times have to:
chant or sing hymns or religious texts in public
officiate at milestone ceremonies and rituals, such as weddings and funerals
lead public liturgies of worship, especially on religious holidays
preach to devoted followers without ideally causing them to fall asleep
read sacred writings aloud to others clearly and strongly
inspire fervor in the faltering and the fanatic alike
Would it not make sense for clerics to have access to Perform as a class skill?