As much as I love DuckTales 2017, I do find it extremely disappointing that Donald basically disappears from the show unless it's a Della episode. Especially when they billed him as a main character.
He’s certainly more involved with the main story this time, but I’m not surprised that he isn’t in every episode. Let me tell you why this isn’t a bad thing!
Ducktales has a large cast (many of which haven’t even deputed yet), and the new series is following the formula of the original in that aspect: it’s rare for the whole cast to appear in the same episode. When it does it’s a treat, but not the standard. In both the original and DT17, even main characters didn’t always show up.
People may have different opinions about this, but in my opinion it’s not feasible to tell a good story with every single character present in every episode. Some characters have to fall back temporarily in order to focus the spotlight on a specific character, and then the spotlight shifts, and the focus becomes the other character, etc.
You can’t develop everyone properly and have them interact in a believable non-rushed manner when they’re all thrown together in a single episode every time for only 22 minutes.
The focus keeps shifting, and eventually we will get a Donald-centric episode, just like we got one focusing on Launchpad, one focusing on Webby, etc.
Donald’s one will probably be a Wham Episode, too.