System Novelty and Complexity

I am working on a cGxP Determination assessment, as part of which my clients wants to also be able to make a decision as to the Novelty and Complexity of the system. Whilst I know exactly how to prepare the cGxP components - I am not quite sure about determining the Complexity and Novelty.

The particular system I am looking at has been deemed as GAMP Category 3.

Whilst GAMP 5 talks about Complexity and Novelty - I can’t seem to find exactly how these should be determined. Based on the fact its category 3 - I don’t see the system as complex albeit potentially novel.

What is the best way to actually assess and document such a decision; I find it to be very subjective - for example the IT guys have different opinions to non-IT or Engineering people (IT and Engineering who understand the system more see less complexity and risk than process guys and/or scientists for example).

Any tips would be great!