Dumping Normal Powell makes some sense to me given the emergence of Anfernee Simons.
The 3 small guard lineups clearly were not working. The Blazers bad defensive backcourt need defensively adept forwards to help cover for their limitations. That is why the moving on of Covington is confusing.
They trade N.Powell and have a high quality three guard backcourt, replace the forwards around Covington (keep Nance as 4th forward) and get a backup for Nurkic and Portland are a good team again. A 50+ win team. Not a title contender but a good team.
Instead they dumped Covington as well and left themselves without a single starting caliber forward. They have weak bench forwards and no backup center. That is a lot more work to replace those spots. Keeping Covington was an important step.
Sure looks like they are blowing it up instead of retooling because Covington should have been a key element of that retooling program. I'd have him as the 4th most important piece behind the 3 guards.