I had figured much the same thing in regards to that Sub being worth while after the reading i've been doing the last months. I must admit its a little over-whelming just how much there is to learn on the audio side of this Home Theater obsession as i've been basically consumed by the video side of things in my pursuit over the years do to some bad luck with my TV choices when I first got into this.
I had originally planned to get involved in upgrading my audio back when I first grabbed my Onkyo SR-606 as Circuit City was closing its doors back around 08?
I then started to have issues with our JVC HD-ILA set (my first set that I skipped the warranty on
) which was followed by our bedroom sets also dying around the same time period (one of them was due to go but one wasn't) so I was scrambling for a bit. Of course this lead to me being forced to grab a low budget solution TV for my HT and my first Plasma a Panny 50X1 which abruptly turned me into a plasma guy
so it all worked out on that end.
That said once I had bought some short term solutions for bedroom sets with 32" Toshiba and Samsung 720P LCD models my HDMI went out on the Onkyo just as I was getting set to upgrade my speakers.
At this point I turned my attention towards getting back up to a 1080P display and found a steal of a deal on a 50VT20 open box from BB at the begining of the year for the same price I bought my 50X1 for back in 09 so I pulled the trigger.
So only now have I finally turned my attention back to the audio side of my home theater, first came the C-21 as i'd always had an issue with the dialog not being crisp enough through the old center speaker and it was a night and day difference just wow but it over whelmed my other speakers and even my untrained ears could tell the soundstage was poorly balanced.
I then came across newegg running the promo code on the BS-21's for $50 a pair and pounced on it to get my fronts and side speakers for a 5.1 set up.
Now i'm focused on in on getting back to the HD audio codecs for my new speakers. As you said the 1712 seams like the more ideal reciever for me but i'm kinda torn on the idea because i'm not sure I can get $400 up before they sell out and I was floored by the HD codecs when I had them even on crap speakers so i'm sure to be thrilled with the 1612 plus the wife already wants to kill me....
She doesn't even know i'm planning to grab either a 65VT50 or 65VT60 next year around April or May depending on if the VT60 hits 9G Kuro blacks.