I also listen to a lot of music concerts on Blu-ray (I'm a huge fan of those).
I have the Onkyo TX-SR876 (great with those) and I also have a Paradigm center speaker (the older CC-300) and used the Paradigm Titan as my main (A) side surrounds, and Paradigm Atom as my rear surrounds.
Everything is just sweet and marvelous.
Your Outlaw Audio amp is a great amp, it will sound very good (as in musical) with your system, for a fact.
And a Paradigm CC-570 or CC-590 center speaker would be a very nice upgrade.
* I must have over 50 Blu-ray only Music Concerts, and over 300 DVD Music Concerts. I also love multichannel SACD and DVD-Audio. So, a good center speaker with clear and articulate voicing is of prime importance for me too.

And I even run my Paradigm CC-300 center speaker Full Range for these occasions (useable bass down to 25hz).
Cheers,
Bob