Probably the usual complaints about package load and compilation time.
These aren't fundamental issues with the language and will be solved by tiered compilation (there's already an interpreter mode, just have to integrate that with normal use), separate compilation and incremental sysimage creation which works with the package manager.
What particular language features of Julia make that trade-off? (Not a rhetorical question, I'm not disagreeing with you, just curious; I'm familiar with Python, not really familiar with Julia.)