I doubt Uhuru would "hide" such discussion with Ruto. It just probably that Raila insisted on Uhuru being alone. Ruto has been letting Uhuru have all the lime-light he needs because this is his legacy. It been that way post formation of Jubilee. It no longer the URP-TNA coalition days. So Uhuru as PORK of united Jubilee party doesn't need Ruto on his side when announcing cabinet or when receiving Raila & ODM defectors.
It appears all the NASA folks are keen to cross-over and join Jubilee. However the line up is clear. Ruto is deputy and the anointed succesor. That is not up for discussion or debate of any form.
Post 2010 Katiba - no tribe can do it alone - it got to be a coalition of two or three - I don't see how Uhuru will abandon a reliable partner for someone like Raila. That someone has to be smoking something else.
Also I see people talk about GEMA - there is nothing like that - there is Uhuru - the defacto GEMA king. Just like there is nothing like Luo - you're talking Raila. The same with Kalenjin - it just Ruto. Perhaps you can talk about Luhyas - & maybe Kambas - and of course the rest where the folks need to be convinced this way or that way.