While academics (with far more wisdom on the situation) may still believe that Saleh will ultimately go, I’m no longer so sure.
Fresh from his success in killing Osama, President Obama seems to be walking a slippery slope by okaying a failed targeted assasination of Anwar al-Awlaki in Yemen. The United States government - as directed by President Obama - is sending the absolutely wrong message to Yemeni protesters with this move. Only six days later, Salih had another dozen protesters killed (most in Sana'a).
Everyone knows that previous to the Arab uprisings Saleh only had a tenuous grip on the country. It was widely reported that, apart from oil and LNG facilities, the regime was only capable of governing a few cities. With so many people focused on AQAP and the security implications for the "western world," the question has yet to be asked as to whether the internal security situation relative to governance has changed to any significant degree?
Regardless of the defection of top generals, I don't think it has much. And from the looks of things, I think Saleh might agree.