Apart from Arsenal and Newcastle most top EPL teams are underperforming. Like you pointed out it might be that most perceived low classed teams like Brighton and others have upgraded thier games making them very difficult to win. Most of these teams have quality coaches that have led their total transformation.
Poor defending would always make a goalkeeper to lose confidence. Lose of confidence is the cause of cheap blunders. Tottenham's problems is not Lloris, the total team is in shambles that Conte must do something or risk being sacked. This was a promising team that was tipped to win the EPL and at least Harry Kane would laid his hands on a trophy before he retires. Harry should understand that he is an eternal Tottenham legend and I think that's enough for one of the world's best but most unfortunate striker.