I can see good military reasons why one shouldn't necessarily detail "specifically which aircraft can go where" though there may be pressing reasons why the taxpayer should know that, if limitations are the result of poor procurement.
As to which "capabilities will be lost if one type is sold early or another retired early" then witholding the information can only make it easier for politicians to take easy and expedient courses of action, secure in the knowledge that the implications of those actions will not be picked up by the electorate or the opposition.