I agree. It's not fair to call a player a bust when they've had literally less than half of a season to settle in. IMO a player needs at least a full season before they can really be judged. These guys are with a new team, in a new league, in a different nation and culture, where everyone is speaking a foreign language. That's a lot to adjust to.
And it's not really fair to criticize the team for not having the depth to deal with all these injuries. No club can predict and plan for an injury crisis of that magnitude while having a practical squad size. They'd have to have a squad of like 35 players for that.
Aubameyang, Mkhi, and Sokratis have had over a season to adjust. Sure, it may be a little premature to call it on Immobile, but all signs currently point to him being in the same boat as Aubameyang (good at times, but not fulfilling his potential).
As for the injuries, Dortmund has had one of the worst injury streaks I've ever seen in professional sports, but that doesn't change the fact that every big signing Dortmund has made since losing Götze has been at the attacking end of the field. They haven't made any serious signings to shore up the midfield or defense aside from Sokratis.
It's not like all of these players are terrible. They have plenty of good players, and they easily have enough talent to challenge for the #2 spot in the Bundesliga. The problem is that this talent isn't developing into actual quality on the pitch, and at some point, a bad trend turns into what defines the team. I don't see how you can go three full months and counting and still say it's just a "bad streak" or whatever phrase you want to use. With over a third of the Bundesliga season done, one of the worst offenses and defenses in the Bundesliga, and no wins against quality competition to speak of (the Gladbach win doesn't count), you can't really bring many positives out of the season at this point. Every time we think it may be passing, the team just relapses into a horrible performance.
Of course, a poor performance in a game that means little away from home doesn't mean the end of the world, but it's a continuing trend in a place (CL) where BVB was supposed to be actually performing well, and they really needed to perform well here to spring them into this weekend's fixture with some confidence for a much-needed win.