My DS was accepted to Harvard starting this fall with one year of Spanish followed by three years of Latin. He disliked the way Spanish was being taught (only one Spanish teacher in his school), but the Latin students were all in love with the class and the teacher. So he switched to Latin and never looked back.
He did not address the switch in any of his essays, nor was he asked about it in his H interview. Clearly, in his case, this did not hurt him.