Regarding polyphony, things have changed quite a bit with all the dedicated polyphonic modules lately.
Building a polyphonic modular from separate VCO's, VCA's, VCF's, etc. is no longer necessary. Moreover, these dedicated polyphonic modules often provide ways of controlling the voices without sending separate CV/Gate to each voice. That opens up entirely new workflows, which inevitably result in different music. Many of these modules are also not significantly more expensive than a regular oscillator, nor do they require excessive amounts of modules to support them.
So I'd argue that polyphony is no longer an issue in eurorack, it just often requires a different approach.