In German, I would use the term "vieldeutig". On-line dictionaries yield "ambiguous" as the only translation of this German word. But I agree that this is not satisfactory for your case. "Ambiguous" has a negative value aspect, while you seem to look for a neutral term. Possibly there is none because, in the end, is there anything which is not open to different interpretations? The closest match that occurs to me is "multifaceted".