Some STARs at airports near mine are for prop and turboprops and others are for medium and large jets.
I don't think there is any airport in Europe which has a significant traffic density and which actually operates the STARs which it publishes (usually about 50 of them
).
It's all radar vectored, and ATC don't have a problem with that.
If an airport goes procedural, its capacity falls by a factor of several times.
SIDs are operated more than STARs but at the busiest airports you get taken over by radar anyway, when departing.
Anyway, GA won't be going to any of these airports (just as they don't currently) because the management there has set up a price-fixed handling cartel comprising of Signature and Harrods handling at £400 a pop
Why on earth the whole IR issue is not addressed with a view to making it more akin to the US model is beyond me
BECAUSE the USA is AMERICAN