Half of dm.MWParameterModel is dedicated to looking things up in the parent template's spec. Despite that, ui.MWParameterPage manually looks up the default value and autoValue because there are no getters in dm.MWParameterModel for those things, for no good reason whatsoever. Those getters should be added.
What's even worse is the "if there is no real value, set the value to the autoValue" logic (added in https://gerrit.wikimedia.org/r/168204 ). Currently this logic (which is fundamentally DM logic) is in ui.ParameterPage as well. Instead, MWParameterPage.getValue() should be smart enough to return either the real value or the autoValue if there is no real value.