I didn't like the Stotts hire initially but he grew on me to the point where I thought he was doing a really good job. However, much like Olshey recently I have begun to question if Stotts is really doing that well. I don't think lack of talent is an excuse. Here are some of my issues:
Passing
Blazers were of course last in the league in assists last year. They were the only team in the league to average less than 20 assists per game. Team passes per game they were 28th. Both the Rockets and Thunder were bad passing teams as well so maybe those numbers aren't necessarily indicative of a successful offense but I think we can all agree that when the ball movement is crisp and the Blazers make the extra pass it seems like their offensive output and record are better. The coach is responsible for getting the team to make more passes but I feel Stotts allows too much isolation.
Fast Breaks
Portland was of course dead last in fast breaks as well. This is on the coach as well. I have seen hundreds of times where Stotts is yelling "Run, run, run!" after a rebound but they rarely do. If your players aren't doing what you want them to do after 6 seasons then you aren't doing it right.
Rotation
Last season Portland had one of the greatest advantages over other teams in the West (except GS) which is continuity. A lot of other playoff level teams made huge changes to their rosters. The Blazers should've came into the season ready to take advantage of the teams learning to play with each other. Instead they got off to another poor start for the 3rd year in a row. Stotts spent the first two months of the season dicking around with the lineups while the team struggled. It was only when he finally started being consistent with the rotations that things started going well. However, there were several games where Stotts reverted back to letting other teams dictate our lineups instead of forcing them to change to us.
Defensive Pick and Roll Philosophy
I hate the automatic switching on picks. Before last season Stotts said he considered changing up his defense but decided against it. I believe the defense was better last year because Nurk personally doesn't auto switch and gets stuck on guards much less than other players. This is a really overlooked skill. Collins will learn but he got stuck on guards a lot. In my opinion you need to mix up your defensive coverages on the pick and roll. Throw different looks at them. In the Houston game where the 2nd unit almost came back and won they were blitzing Harden forcefully every time he ran a pick and roll. After years of getting the switch he wanted every time he played Portland he had no clue how to attack it. Now blitzing the pick and roll every time isn't the right play either but that brings me to my point. You have to mix up what you do. It's more than okay to switch sometimes but when prime Dirk only needs to pretend he is screening Dame to get him to switch on him every time and then gets the ball at the top of the key then the other team has a major advantage. If they have no clue if you are going to trap, hedge and recover, switch, or blitz the pick that is where you can really become an elite defense.
Playoffs (This Year)
I'll give Stotts a pass last year because we had no size with Nurk and Davis injured. As mentioned several times in this thread, the Pelicans pick and roll defense was incredible in that series. Why continue to run it? How come other teams can come up with creative ways to get their stars shots? How about trying Dame off the ball if they are double and triple teaming him? In a series you have to be able to exploit mismatches. It might not be fair but it is on the coach to make the adjustments.
Most of these things are correctable and almost everything else Stotts does is good but they are things that a coach can affect no matter if he has the talent or not.