Paul,
I am not buying everything you are saying because I am not sold on the metrics you use. Any stat that takes into account the dumpster fire injuries caused this team last year to prove a long term trend just is not relevant in my opinion.
Having said that, if the front office and training staff believe that Murray is sound physically then he ought to be on the number one pair. We do not know what the braintrust thinks about Murray right now, they may want to see if he can be healthy for a full season before putting him out there as the top defenseman. If you make him #1 now, you will be shelling out $$$$ since he is an RFA at the end of the season.
At this point the season is clearly lost, so it might be that in a month or two as the playoff chances are put to rest once and for all the staff might move him up.
Or maybe they can find a team who needs a 2nd or 3rd pair defenseman at the trade deadline, eat some salary and trade both Johnson and Tyutin and see what the rookies and 'Goldbeef' (as some call him) can do in the NHL.
It is awful to even be talking like this, more failure, no playoffs, no cup