First, this notion that Danny screwed up the bench is really arrogant. PJ retired, Posey got more than anyone ever thought he would, he could barely get a 1 yr deal the year before, acting like it was so easy to keep the exact same team ignores the facts. NO does not have KG, PP and RA's contracts, when you load up like the C's did, all you can afford is a cheap bench, and luckily Posey was cheap last year. We would not have signed anyone to that deal the year before, including Posey, so that was not going to change this year, in spite of how huge Posey was.
About the whole 2nd unit discussion, I think something that is being overlooked is that the playing of them as a unit, rather than working them in with the starters, is a regular season strategy that Doc is not wed to for the rest of the year, and certainly not in the playoffs. The C's may make a move, or they may not, but in either case, playing all those guys, despite their flaws, either helps to identify which guys might merit mix-in status, or continue to reveal what the most glaring need is to address(even if everyone here already knows). Pose was a known quantity who could be mixed in right away, we have nobody like that now. Mixing in, would not allow those guys to get better as much and/or show which ones are worth promoting or discarding from the rotation.
It is still only 33 games deep, more than 1/2 the season is left. Doc is trying to get starters predictable minutes, while giving several bench players a chance to emerge(or not) and the C's still have the best record in the league at this point. This is not going to be the playoff way of playing the bench, guaranteed, so how we match against other teams' second units right now is basically irrelevant.