> streets of Baghdad governorate and some other cities were classified based on this proposal." & "no harm in using it till approval or a better alternative."  
No, and please do not edit tag values to proposed ones. We shall only used the official government classification system of the roads, and we shall not classify them based on our opinions.               
  
>the proposal was made after a good amount of research"     
Were this research published or discussed?  
  
> I only changed 5 roads.   
No, you changed many many road classifications, just last 3 days you made this changeset and those other changesets 152559788, 152559016, 152558508, 152558069 etc.. You has tens or even hundreds of changesets when you changed road classifications based that proposed tag, which is not the right thing to do, and shall be checked and reverted to the correct values manually.        
  
Regards.  