My only issue with BoD (and lately with all released raids) is the difficulty curve. It's beyond stupid. The amount of pulls on last boss can easily exceed the amount of pulls you need on every other boss in raid combined, that's terrible design. It's really no fun spending 200 pulls on all bosses and 300-400 pulls on one boss alone. It's bad, it's exhausting, it's tiring it's not fun. For an avarege guild, like those I raided with in recent times, it's very common to spend like 1-2 months to get to last boss, and then spend 2 months on last boss alone.
There was no joy after killing mythic Argus, no happiness, just a big loud sigh, say some bad words to player who was lucky to get that mount because you will most likely never do it again (unless 2 expansions later and you solo it). I would rather spend 500 pulls in total spread somehow evenly accross the raid than do 8 bosses in 150-200 pulls and last boss 300 pulls.