It would be helpful if we could define "simple" types that are based on primitive types. This would be useful for providing values for facet attributes in one place:
<SimpleType Name="Char80" BaseType="Edm.String" MaxLength="80" FixedLength="true" />
<SimpleType Name="AmountInFInancialReportingCurrency" BaseType="Edm.Decimal" Precision="30" Scale="2" />