I finished the new expansion yesterday, so here are some thoughts.
The new class (Death Master) is great, feels pretty powerful too. Since I was able to boost it to lv 105 and grab a free 105 weapon from Astoltia Defense. While a bit fragile (caster armors and no shield will do that, I guess), it's really fun all around, both as a DPS and support.
As for the v5.0 story, I enjoyed it. Although mostly for the characters introduced, since actual things that happened were just your regular DQ fare (although there were some really good moments, especially near the end). One thing that surprised me was how short the main story part was. I think I finished it in 2 afternoons, which was a far cry from previous expansions, Shadowbringers, and even the total length of the 4.1-4.5 patches.
On the positive side, there was almost no fat, running back and forth between npcs just to advance the story forward. With a similar teleport system as the cube in 4.x, moving around was really fast too.
One more nice change is the ability to choose the difficulty for bosses right away in 5.0 content, I hope they keep this policy going forward.