I'll start from here
> has the flaw of being dry
Given that, in my opinion, there is no such thing as a perfect VST since everyone has their own pros and cons; before choosing, it is always better to listen to demos and look for YouTube videos that show the VST in action regarding its components. But regarding demos, it must be specified that some companies entrust the creation of demos to very talented artists who produce masterpieces, so it is better to look for demos where individual sounds can be heard.
Therefore, absolute flaws do not exist (and in particular, I will later tell you the advantages of a dry sound); what matters is one's own personal taste. Take strings as a reference: for example, Hollywood Strings is a library with a strong Hollywood style, yet it is very flexible because the studio has a very dry sound, making it highly adaptable to one's needs. Not by chance, it works well in very slow legato, as the good Thomas Bergensen uses it, providing a very compact and majestic sound (large string sections capable of supporting the rest of the orchestra in terms of volume).
> so you have to create the ambience yourself
Another point to pay attention to is mic positioning; there are a couple of widely accepted philosophies, but pros and cons always emerge:
a) recording instruments in their natural position (they sound more realistic but are less flexible)
b) recording instruments in standard close position (difficulty in recreating 3D ambience during mixing, but they are more flexible)
Furthermore, it also matters greatly where the VST was recorded (studio, church, theater, etc.) and if you have a dry sound it is workable, but if you have a wet sound... much less so. Remember that reverb can be added, but it cannot be removed... therefore excessively reverberated samples can be difficult to use.
So, still referring to strings, I will point out some parameters that I think you should keep in mind (...also because strings are capable of exceptional dynamics and incredible sound variety, and finding an exhaustive library is practically impossible) to understand if the library is indeed more or less valid:
- crossfades in dynamics
- samples with and without vibrato
- True legato
- Run simulator
- Sampling of different bowing techniques, at least staccato, spiccato, pizzicato, etc.
- other samplings such as effects, flautando, con sordino, glissandi
Additionally, consider that strings often present the problem of divisi and soloists, and often VSTs do not include these samplings either... the problem of divisi is a partially unresolved issue in modern VSTs because sampling both entire sections and soloists would involve an enormous amount of work, and it is not done. In these cases, it is the task of the MIDI orchestrator to imitate divisi using tricks with mic positioning, and for soloists, there are often dedicated libraries.
In general, one must keep in mind that large string sections are sampled (10-24 first violins, 10-20 second violins, 6-14 violas, 4-12 cellos, 3-9 double basses) specifically to compete in terms of volume with a full orchestra.
