Okay, fair disclosure: I've never met Chris Roberts, or (that I know of) anyone involved with SC. I've also never met Dean Hall, nor had any personal or business dealings with him.
Now, that DayZ bit: first off, as a mod, DayZ offered something playable and an experience found nowhere else. That's not true of SC, at least at the moment. People bought ArmA2 to play DayZ, and they did.
Second, the "shortcomings" have been mentioned before: ArmA (and OFP before it) has a huge map; without doubt more complex and populated than any "moon" SC has currently on offer. I personally like the pacing of longer times between highly lethal engagements. Sure, I also enjoy your face-shooter too, but they're very different things. It's like the violence of The Good the Bad and the Ugly vs. Black Hawk Down. Or hell, if you want a ton of death, take the Wild Bunch: in games where killing is the only meaningful action one person can do to another, the visceral impact of that action can vary depending on whether you spend 1 minute or 1 hour preparing for it.
Now, what about Dean Hall and BIS? My guess (and again, note my disclaimer above) is that he left when he figured out that there were a couple people ahead of him in line to get rich off of DayZ. But that doesn't mean that Marek and Ondrej == Chris and Erin. I mean, a modder for Bohemia Interactive went on an extended vacation to climb Mt. Everest, the proper way, from Nepal. I'll pause while you figure out how much that cost, and you can join me in imagining that BIS recognized what DayZ did for the company, gave DH a fat bonus, and tried to retain him. But at the end of the day, ArmA, the engine, and the development is run by other people, with other priorities, and as a middleware scripter, the only benefit he'd be getting by staying on would be that those issues in the past he used his scripting expertise to get around, now he'd maybe get someone who worked directly on the engine to fix, when the time was ripe.
So, yeah, BIS, in the business of doing military shooters and selling simulations to the military, now finds themselves with an unexpected hit on their hands, and the commitment to release it as a standalone, without a lead designer. They're not the kind of outfit that pays top koruna for some SH established game designer, nor could they compete in that market if they tried. But they've had a product that, while being disappointing in its current state (is it released now?), had a huge cultural impact, and has spawned a minor revolution in gaming.
That's completely different from the case of a washed-up FMV Cutscene director deciding he can produce and direct the BDSSE and taking over half a decade to deliver unplayable garbage.
Oh, and as an aside: I notice that the IMDB pages of the key players in this drama include every Star-Citizen-related Web Video produced. Do you think CIG is paying scale?