What virtual synths are designed best for dynamic playing?

All virtual synths allow velocity, after touch, etc. It's more of a matter in how the preset was programmed.

Probably the closest to what you're imagining is the combination of an MPE hardware with a virtual synth.

Most synths can do this, but as Pier already mentions it is my experience that MPE patches specifically programmed for expressive playing are mostly found -unsurprisingly- in synthesizers that sort of exist for that purpose. So I can wholeheartedly recommend ROLI’s Equator 2 synth. It works with and without MPE controllers but has great presets that deliver when it comes to expression.

Another fine synth in this regard is Brian Clevinger’s Plasmonic.

Finally, have a look at AAS Chromaphone.

FM8 comes to mind.

Virtual Virgin said:

where velocity end expression are integrated in a way that is derived mostly from acoustic principles where timbre, transients and envelopes are mapped in ways to mimic physics?

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Like shapes that mimic natural decays or timbres that reflect real resonating bodies?

Because then Pier is right, it's the programming and less the synth. For adjustable modulation shapes it's hard to beat Phase Plant. For amazing timbre it's hard to beat U-he. To be able to route the modulators and effects in such a way to achieve what you're looking for, either would give you that. If you want an "easy" physical modelling synth, maybe try Plasmonic, or go with Zebra (...and Z3 might be out in a few months or 2025). Falcon or MSoundFactory can also satisfy you for all of this, and may God have mercy on your soul.

Not sure if this is what you are looking for, but it is very good: