To Focal or not to Focal

Focals tend to be hard on amplifiers, delivering sub-par bass unless your amp is pretty stiff.  They also have a unique sound and off-axis presentation which has a lot of fans, but also means you should not go there without listening.

Also, room acoustics matter. 

@erik_squires good points about the Focals being power hungry and the room acoustics.
I used to have DNA 0.5, DNA125 and 225. All are great amps. I also owned Rogue ST100 with RP1.
It’s been a long time, probably 20+ years since I heard those NHT speakers, but I still have the AC1 center channel that I just recently replaced with Focal Aria CC900 purchased together with the standmount Aria 906.
The CC900 is a better speaker than the NHT.
And the Aria 906 have definitely surprised me in a good way, driven by a Marantz AVR.

So my recommendation would be to upgrade the speakers. Keep the RP1/DNA1 combo. I think you’ll like the Focals - they’re warm and very engaging sounding speakers.

Not

I should qualify. Not because the are not decent speakers, they are. However they are stupidly expensive and you can get the same or better quality for much less. 

In my opinion to Focal or not to Focal is to Focal. Might check out this vid comparing the Chorus W to the Aria which I’m assuming “may” have similar voicing to the Thieva. 

I’ve had Aria and currently my main speaker for the past few years has been the Chorus 836W. I’ve tried other more expensive speakers over the past couple years and keep coming back to them. This video pretty much sums up the difference I heard in my room.