Definitely agree on both counts. One of the best things I did during development was to do an internship where I could be close to potential users. Porting an existing application was also a helpful forcing function, both for the feature set of the language as well as performance.
So far I've focused on HPC users. I think focusing on a niche carries some risk that the language might be too narrow (and this is particularly true of HPC). But one thing I like about HPC is that HPC users really know what they're talking about when it comes to performance.
So far I've focused on HPC users. I think focusing on a niche carries some risk that the language might be too narrow (and this is particularly true of HPC). But one thing I like about HPC is that HPC users really know what they're talking about when it comes to performance.