Although I never like mid-season driver changes, this one is a non event to me. They are merely replacing one rubbish driver with another who brings more cash to the table. The team's first priority is survival, so, given their financial condition, the move is completely understandable.
Its not like they are losing a driver with a surfeit of talent. Senna only got a drive because of the surname he has chosen to use. That name opened lots of doors for him, but it also raised expectations. He has failed to deliver!