I see possibility to optimize VpeNodeInvocationHandler - method invoke - there are a lot of calculations behind the method.
for example in case if the object type is String - you call ElService.replaceElAndResources - which perform a lot of complex string analyze operations.
to speedup calculations - there is a sense to save calculated value and return calculated results during subsequent function calls.
ordinary you and third party creators call this function often.
so this simple pre save strategy will speedup page rendering process.