There are lots of good points here on both sided of the fence. I have no fondness for sound bars, and no dog in this fight.
My main objection to them is the marketing hype that surrounds them (look I made a pun!). I believe some of the descriptions and claims made do indeed edge into scam territory. My example of Bose marketing is an extreme. But take a look at some of the packaging. They do make them sound like bonified hi-fi products. There is certainly no disclaimer that it isn't as good as a true system. And the audio-ignorant masses will believe the hype. That's the extent of the "scam" aspect of it for me... misrepresenting it as a hi fi system, which admittedly not all manufacturers do.
The fact is they do sound significantly better than what typically comes in a modern TV, even the cheap ones. For your average non-audiophile consumer, that may well be good enough. My lady's brother just got a $120 Samsung sound bar at a local big box store. He thinks its the greatest thing. It IS a very significant step up in sound quality from the TV without a doubt, and you do get some semblance of base from the 5" sub module it uses. And he can stream music from his phone like its a stereo! It's a hell of a lot better than listening to the phone! He's happy as a clam with it. And yes, I've let him hear my system. It doesn't matter to him, he has no interest. He couldn't stay seated in one place long enough to listen to and appreciate a real system anyway. He just wants a better sound when he watches Game of Thrones.
If Sennheiser wants to market the mother of all sound bars... why not? It may be the worlds best sounding sound bar. And in some installations it might be quite good and actually better a set of small monitors. And the well-to-do audio-ignorant types and their significant others (who of course would despise real audio equipment being on public display in the living room to begin with) will be told that Sennheiser is a high end brand, and they can boast about it to their equally audio-ignorant friends and relatives. And marvel at it when they watch a movie together. They don't know what they are missing, they don't care, Sennheiser makes money, the market for sound bars expands. Pretty soon the Chinese will be exporting 13 driver sound bars for 1/3 the price.
Will it spur more interest in surround? Sure, maybe. I don't see how it hurts.
Will it start a great migration to get consumers on a path to buying MCH music? I doubt it. They'd listen to it on that bar and compare it to plain old stereo and figure there's not much difference. Because on a sound bar, there probably isn't. But knowing they have the capability to play it may well be a redeeming factor.
I say buy one if it makes you happy and it fits the situation Just don't tell me its a hi fi system in a shoe box. I know better.