In addition to what's been said already, the A16 is 96kHz while the A32 is 192kHz when it comes to processing. So if one has a 192kHz source and wants to do 1:1 without resampling, then the A32 is the choice. Given that all the other options with room correction on the market are either 48kHz or 96kHz, this makes it unique.
As far as the processing power goes, the A16 is using a Intel i3, the A32 Intel i7. The A32 is generally considered upgradeable, the A16 is not. So buy it "as-is" when it comes to hardware, the software can of course be updated. There's a AVB interface for the A32 in the works, if that matters. No word on that option for the A16 yet.
Being a Meridian owner, this has me looking at the Lyngdorf MP-60, which offers this as an optional extra for a small premium over the base model Trinnov.
I wouldn't worry too much about D/A, A/D. When done right, there's absolutely no difference. 10 or 20 years ago it was a big thing, today not so much. I've been using fully digital systems for a loooong time and recently digged a little deeper and did double blind tests with "modern" equipment, because I was told by others this isn't a thing anymore and didn't believe it. The mistake that people make is not having matched signal levels, interference on the cables, not having a matching calibration between inputs (even 0.5dB difference makes a large difference) and so on. A potential issue could be really long cable runs, say if you have the processor mounted in a server rack in the basement and the cables run through the whole house, but that's usually not the case.
What really makes a difference is having digital DSP based crossovers vs analogue ones, but the additional D/A in the processor and A/D in the 271 doesn't matter. Same is true for speakers such as Genelec, Adam and so on, there's no difference in using analogue vs digital inputs.
That being said, the MP-50/60 isn't a bad processor, I think it's much more end-user friendly than Trinnov and provides good quality. But if you don't need the end-user friendliness, I'd forget about the digital out and not think twice.