Agreed, that would be ideal. But it's also a little unrealistic in the short term - most languages don't have an interpreted and a compiled mode. I think there just isn't the dev manpower.

It's more useful to think of Julia's latency as a fundamental constraint of the compilation model. People don't complain that Python can't deliver static binaries, or that C++ is unsuitable for scripting. Julia's compiler can do both (although the "static binaries" haven't materialized, because noone seriously works on it), but the tradeoff is that you suffer from latency. That's fundamental. Future versions of Julia may cut the compilation time down further, but it will never be instant or even close to instant.

So, like other languages, it means you have to look at the strengths and weaknesses of the language for your use case. For myself, I can't imagine a situation where I want to plot something right now and not in 15 seconds. Whenever I plot something, it's always after minutes or (usually) hours of data analysis. Most of my Julia use is either long, interactive sessions where ten seconds of startup doesn't matter much, or long-running pipelines where it doesn't, either.