It's hard for a non-native English speaker to figure out what is the subject in the following sentence. Is "a different approach" is the subject of the whether phrase? Then, it should have been "whether a different approach to delivering the needed capabilities is in order?"? Considering the context, it seems "the needed capabilities" should be the subject.
Because we have already spent the money to deliver a “legacy” system, we assume that we have to keep spending money on its continued existence. But why? Shouldn’t we be deciding whether the incremental spending is worthwhile in itself, or whether a different approach to delivering the needed capabilities are in order? Even if we are just “fixing” or “maintaining” the system?