Is it ok for singer to have a bad diction?

My boyfriend is the leader of the band which I sang in, but recently he removed me from the position of vocalist, because from a certain moment my diction became very bad and I can't pronounce all words properly. I think he is wrong and diction is not the main thing. What do you think? It's his idea to create a poll. He said that if the result was in my favour, he would consider it.