Some of these comments... Jesus H Elivs...
You are getting the sound quality of one of the best units in the world. You are also buying something from a product line, that has 2, 12 and 16 channels.
Does that make it perfect? no.. however this would have done me up until yesterday when I added 2 extra height channels. I have a media player, games console and you could argue whether the computer is relevant as it runs as a server only and can be remote accessed.
So if I had to have the outstanding picture quality of Sky or Virgin I could, or I could rub jam in my eyes and listen to the radio.. point being 3 HDMI is enough for the majority of people that want but can't afford the performance of an MP60 as is marketed and priced accordingly.
Video connectivity is a £200 problem that is reliable and set and forget and lets face it you'll probably get that knocked off the unit anyway. You have a bunch of streaming options in there, including chromecast? I'm pretty sure this was held up due to a chrome cast license, but regardless, they are built into things like the Nvidia Shield and you have Roon etc built in to the unit itself.
Also, smaller companies don't have the purchase power of D&M for example - saying things like I can get this £300 unit with 6 HDMI, well ok let me know how that works out, I bet it sounds superb......
And good luck getting something decent sounding for less that actually works, because it's not JBL, Arcam, Nad or Emotiva. By all means, search the forums on those units, some of which were released before their room correction/software was finished and also without it entirely.
Bringing me on to that subject..
I am a screaming Anthem fangirl, I have had 3 generations of their products, I still use one of their 5ch power amps and have Paradigm subs, I think they're great but ARC is not Room Perfect, it just can't deliver the same results and Room Perfect's nearest working Dirac neighbour (remember not all Dirac is created equal) is more likely going to be on Storm audio products, which I'm not sure if you've looked, but they aren't exactly cheap, just like the wizardry of the Trinnov ALT 16 using TEQ.
Buy the MP60 (or whatever) if you want this level of music and movie sound with more channels and connectivity, but the difference between £8.5k and say £12k is a world of difference for more people than not. They are already punching up beyond their budget. You just have to look at what installers are using and how terrified most people are of their wives to see how it all fits in with the marketing in tow.
Similar with the TDAI 1120 and yet they are being gobbled up all over the EU.
On the point of HDMI 2.1 in this day and age - what are you using that for exactly in the next bunch of years*? there's no physical media, or streaming services even thinking touching this and as you probably know, Netflix has just chopped their 4K bitrate, Sky and Virgin's HD is bollocks. Again they're not marketing themselves to home theater owners, but to millions of average £600 HDTV family lounges, that is their bread and butter.
All said, the pros vs the cons (with work arounds) don't leave much to argue about. In my own personal opinion, I think had they even released it with 4 HDMI, there would still be some screeching womble (who can't afford it anyway) who'd still be complaining about something else. The pearl clutching is hilarious, vote with your wallet.
*obviously not including the 2 PC master race users that would have this in their setup.