Like most of Neverwinter's campaigns, the River District can be summed up as "more of the same, but a bit different". Here's what I like and don't like about it so far:
+ The environment. While one could argue that a slightly twisted cityscape doesn't make for the most exciting adventuring zone, I like being back in the game's eponymous capital.
+ Zone size. Sea of Moving Ice taught me that bigger isn't necessarily better, especially when a single round of dailies takes ages simply because you spend ten minutes travelling to where you need to be. I like how the River District feels much more compact.
+ Variety of activities. Instead of being asked to do x number of daily quests every day, you're only given a single quest that basically asks you to "do stuff" and you can pick your own activity mix to complete it. This allows you to change things up at any time.
+ Better treasure maps. The treasure maps from Sea of Moving Ice have made a return here, but since the environment contains a lot more notable points of interest, you actually stand a reasonable chance of finding the treasure even without a guide.
- Mob density. This might be a side effect of the small zone size, but mob packs are plentiful and hard to avoid. Additionally they seem to be tuned to hit in such a way that a purple quality mount isn't enough to not get knocked off anymore, so I'm getting dismounted pretty much any time I aggro anything at all.
Overall, the good seems to outweigh the bad so far.