Well, Coburg. It goes like this.
Firstly, there's a thing called context; it goes a long way back to Lamby citing SMartin as a striking contrast to Hampson over 2016, thus referenced in posts between us.
Secondly, he was Nank's direct opponent this game. IMHO, although Nank battled hard, Martin clearly beat him soundly by most parameters, although some didn't seem willing to be honest/realistic about this.
Thirdly, Champion Data. Some rate it; others thing it's crappy. (e.g. See some of Zip's posts!! Don't they rate Sheds as elite too? That's one I'ma little more accepting of than Zips). TBH, I've never really examined it that closely. Think I once had a look for their website and either didn't find satisfactorily/you needed login crap etc./or found it boring. Can't remember. As I've said before, I'll never claim to be a stats guru. I do find too many boring and tedious to pore over and suspect nothing that revelatory may be hiding there. So, in short, not sure CD is all that indisputable a source.
Personally, from my POV, Nankervis' effort in 2016 has been really good, but not sure I'd call him elite at all yet. He hasn't had a decisive win over any of the ruck opponents he has played as yet, and well beaten by Giles (assisted by Vardy) and S.Martin. He has his best ahead of him and will benefit from greater support. Griffith's return for a start.