I wish the Julia ecosystem was a little more integrated: there are a lot of different competing libraries that ostensibly do the same thing. Python has the advantage that it's obvious what you should use: numpy, Pandas, scipy, statsmodels, matplotlib, etc.
With Julia, it's less clear. Though I think part of the reason is that actually releasing a new scientific computing Python library is incredibly difficult and requires a lot of expertise.
Julia makes it pretty trivial for anyone to contribute a model that has excellent performance. This fragmentation is a common problem among expressive languages.