I am no expert… But I would say that Kontakt by itself (which does include orchestral and jazz instruments), or even Komplete (which gives you some more libraries for Kontakt) is PROBABLY not worthy of being called a fully professional jazz and orchestral package. Maybe in the intermediate range (there are a good range of articulations and adjustable parameters, options, etc.)
What you DO get with Kontakt is a great choice of professional third party libraries (which will cost more).
I do hope that someone who is familiar with East West as well would offer some opinion/advice.
J.L.