I don't know about 'best designed.' I don't really analyze jobs closely. But some highlights for me:

Sohm Al Hard and Arboretum hard I liked because some parts of it had some tanking positioning stuff to do on trash. Keeping enemies in the steam vents/washing off some of the latter enemies rsepectively. I'd like to see more of that kind of thing in general.

Keeper of the Lake just because of Midgarsormr I love him.

The Twinning for the music/visuals.

Aumorat was great. Also love Hero's Gauntlet as a sendoff to Norvrandt.