JBL and Micheal Cole were not huge during their early years in the WWE. For over a decade Micheal Cole was the worst WWE commentator with no fan base. He was face for over a decade, but still often booed because he had not talent on the mic. He was boring as hell. However, Micheal Cole becams a heel in 2010. Since than his fan base grew extremely fast. He is a very good heel. I hated him as a face, and wanted him out of the WWE. Now I want him to stay as long as he stays a heel.
JBL was a nobody for many years. Later he was a part of the APA. He didn't have a huge fan base outside of the team. Later his fan base grew once he turned heel. He quickly became the WWE Champion and one of the most hated heels in WWE history. His full potential was unleashed as a heel.