I'm pretty much in agreement with you TBH. I think Emery needs time but he also needs to show that he has some kind of plan, I sort of saw one earlier on in the season... but don't anymore. Defence has been a major issue all season, we got away with it earlier in the season due to the unbeaten run and a whole heap of luck.
I think Emery and the coaching staff are doing a poor job on defence, as bad...if not worse than Wenger TBH. I don't believe for a second this defence is as bad as the number of errors or disorganisation we are seeing now and have been seeing all season.
Right now we look no better than last season...we did at times look better than last season earlier on in the season...but only due to some encouraging performances in the big games and improved away form...that is essentially the only real sign of progress.
Emery absolutely has to step up now....the performances and results NEED to improve.