Currently we SDE if representation="text" and lengthKind="implicit". This is not correct for xs:string types (or simpleTypes derived from it.) because there is the maxLength facet. (There's a length facet, which seems to be equivalent to maxLength = minLength = length, so just asking for maxLength facet is right.)

This doesn't apply to any types other than xs:string, because only xs:string can carry the length/maxLength facet. E.g., you can't use this to indicate the length of the text underlying an integer because xs:int type can't have the maxLength facet.