I think the biggest damage was CoD's performance.  It's not just down, it's WAY down.  And there was no official bundle for it.  And Assassin's Creed, also a typical console mover, skipped this year.  And aside from Battlefield, all the rest you mentioned were fairly underhyped and Mavia in particular got quite the lukewarm reception.  

And PS4 lowered it's price late in the November game, so that's part of that issue.  But Xbox's problem is that their little game of fire sale after fire sale is a war of diminishing returns.  Having them so frequently has eroded their effectiveness.  So Sony under-utilized their resources and Microsoft has so often over played their hand with the sales that their agression in the Holidays this year just isn't as effective as it has been in the past.  

Hmmm....... what exactly is there to make excuses for?

It's very simple - you offered a bunch of titles that may not have had the selling power of games prior (I say this, because we still don't know if these numbers are legit). Yes, Slim/Mid Gen revisions can (and usually do) help a console's YoY situation, but you also have to have games that people want to buy the system for.

 If these numbers prove true, that would be a logical explanation, not an excuse (unless you're trying to make a claim that things look grim for the PS4 and X1, in which case I would highly disagree, but I doubt you're going that far). 

when I posted I thought it was December NPD... anyway we never did get the final numbers then, right?

No there's no official numbers yet. I wonder why though...

Said no numbers until Jan.  Then deleted their account. So we may never get official numbers.