With John Obi Mikel, the formation can never be a true 4-3-3, because it will always be a 4-1-2-3, considering Mikel plays just in front of the back four.
With the Nigerian in front of him, David Luiz would be given more license to roam. In fact, I envision the Brazilian replacing Mikel in the long term.
Ramires is the engine, whereas Lampard is dependable in possession and will need to score more goals and provide more assists.
The two main queries I guess will be raised?
Why no Raul Meireles?
As of late, he hasn't played well enough. If Chelsea manager André Villas-Boas adopts this authoritarian style in dropping players, then he has to do the same with his fellow compatriots. Meireles will be the first and if José Bosingwa doesn't shape up his defending, he'll be the next.
Why no Nicolas Anelka?
I'm aware he has scored five goals in the last eight games against Bolton Wanderers, though it would be more beneficial to the team if he plays as an impact sub. Plus, Florent Malouda at least keeps up with opposing players whereas defending isn't in Anelka's vocabulary. Same applies with Juan Mata but because he's so brilliant, he gets a pass.