Would this series be a fulfilling read considering Crystal Wishes part of the stories will forever remain incomplete?

7755163
Yes, the Guards trilogy is a complete story on its own. Wishes is another POV of the same timeline.

7755173
Yippee!

Yeah, it's a good read. It's shame that the rest of Crystal's side of things will remain unfinished, likely forever. But it is what it is, you know?

You can always pick up the pen again. Look at stephen king.