[Lewisham]

Depends on what is suboptimal to you. If "suboptimal" is "not optimal for the perfect programming language", then sure. If "suboptimal" is "not optimal for real world use", then no.

Scala's interop with Java libraries has been a huge, huge boon, and undoubtedly drove take-up where there otherwise would have been none. Scala has come this far in a decade. Python is 20 years old. Ruby is 16. Scala came a long way in a short time, and was probably resigned to the dustbin of "that would have been cool" languages without that interop.