Yes we have been signing off most often saying namma Bengalooru...so y not...
As for those who think that this is gonna change the scenario globally and affect negatively...remember it never happend with Chennai, Kolkata, mumbai,etc...for those who wanna do Business the name does not matter....even if itz Bengalooru... Itz just a matter of time...everyone'll get used to the new name...pronunciations also be taken care...
As for those who feel Bangalore is stylish...Namma Bengalooru is Coooool
Enzoy the new name...u'll luv it sooner or later...