any suggestions on what to replace Bluesound Node 2i with

I haven't read the entire thread, so forgive me if this has already been brought up.  You said this is for your home theater system.  If you're running your streamer through a home theater processor, it might not be up to the level of a better streamer.  Streamers don't all sound the same, unless you're playing it through a system that can't resolve the differences.  

I have heard the T2 at a dealer and thought it sounded excellent.  My personal journey involved starting out with the Node 2, then adding a couple of different DACs, and then finally replacing the Node 2 / DAC combination with a TEAC NT-505.  I'm pretty happy with that.  I believe it's been discontinued, so they can be found at a significant discount from their original price.

@big_greg Yes it is for my home theater system which I am upgrading. Yes I run my Node 2i through my Anthem 1120 with the optical cable that the Node 2i provides 

Consider spending your money elsewhere. A two channel preamp with home theater bypass for example. 

Honestly, what you need is a better DAC at this point, not a new streamer. Get yourself a Denafrips Ares II for around $700 and then evaluate the streamer question. 

+2 for big_greg's and other's suggestion re a preamp with ht bypass. This is also what I'm looking at after steering away from the Lumin T2s... dedicated option. Something like the Anthem str preamp has the ht bypass and a relative good dac and most importantly for the op (and me), it will still do ARC room correction.  It will also calibrate 2 subwoofers independently, which is what I have as well as the op. 
Personally, I was waiting for a newer version of the Anthem str before I pulled the trigger or something else that has its functionality but is a notch or two better. But for the op, he really needs to decide if the lumin t2's dac is similar in sound performance to the dac in the Anthem str in this case.

I also looked into the mini dsp HD that was mentioned above. That seemed to do what the op is looking for. 
Also, Roon with the convolution files for room correction would work, but unsure of how many boxes that would need. With someone already having a ht system, I am personally trying to keep box count down.
The main point fir the above is if you're keeping room correction,  you can't just add a dac.
Good luck.