Stock air coolers I would agree, but the Noctua NH-U14S is a relatively high-end air cooler more than capable of adequately cooling any CPU at stock clocks (and performs better than cheap AIO water coolers). It's also recommended by AMD on their list of coolers for Enthusiast Ryzen processors.What level of CPU did the people recommending the Noctua have? Just curious. personally, I wouldn't go air cooling for a chip at that level as I'd be concerned over it's ability to keep the CPU cool, especially if run hard....water coolers are just more efficient at it, the H115i is also quieter than the Noctua as it's fans aren't normal fans. But it's your money and your choice.
As to the case, if you want quiet then the Define 7 is the case to go for. Ordinarily I'd say the case is fine for cooling...however, the Noctua changes things a bit as it moves air differently than the H115i. The H115i (and H100i) both expel air directly out of the case through the roof so airflow through the case is less important...the Noctua still relies on airflow through the case so the case needs better airflow. I'd say go with the Meshify (the one to the right of the Define) as it's a bigger case with better airflow..downside is it's not as quiet as the Define
AIO water coolers have additional points of failure, and if the pump fails, the whole unit needs to be replaced. Their radiators also need to be cleaned regularly. With air cooling, the only likely point of failure is the fan, which is simple to replace if it ever does.
High-end AIOs (as opposed to air coolers) are still undoubtedly the best for the lowest temperatures, near-silent operation and case practicalities/aesthetics, as well being recommended for extreme overclocking.