Sorting rows and return the value as a simple array using EntityFieldQuery
fieldOrderBy is for ordering by a Field API field. 
You want propertyOrderBy('updated' 'ASC').

And the return structure can't be changed, it's always the same (a stub entity in technical terms). You use the id from that return structure to load your entity and get the data you want. I see you've already figured that one out, judging by your code.