The latest events in Azimio have me convinced that Uhuru has probably made peace with the fact that Ruto's lead is unassailable (he receives NIS briefs after all).
It seems to me that his game plan is no longer to install Raila as a puppet, both because of the difficulty of rigging and potential for civil unrest, but also because he cannot trust him once in power as puppets tend to develop minds of their own (Tshisekedi with Kabila, Moi with Njonjo, etc etc)
Looking at his latest moves, I think he's out to control the Azimio Coalition. His Jubilee has haemorrhaged members, but he's cleverly cobbling up small parties and has successfully roped ODM (and now potentially Wiper) into Azimio.
Now, our 2010 Constitution does not officially recognise a leader of Opposition, but such a person remains powerful because of the MPs and committees he controls in the Legislature. That's how Raila has remained politically relevant.
My thinking is this. Uhuru will cobble up Azimio and be the leader of the coalition. Odinga will be the Presidential candidate. Uhuru won't care if he wins or loses. ODM and the rest will be in Azimio, which under the new rules is a coalition political party. Once Raila loses, Azimio Coalition will be under Uhuru as party leader, and he'll be in control of the activities of the coalition, including any potential handshakes with the government. ODM and Raila will be swallowed, and based on the coalition agreement, he'll no longer be in control of his own party. Using Azimio Party, Uhuru can negotiate political immunity for himself and his family.