The 1000-2000kg category will be specially interesting, as this is where the "long range capability at a reasonable price" is located.
Below 1000kg is mostly just VFR-only weekend fun stuff, already being heavily deregulated.
There is a huge opportunity for operating cost reduction. The biggest chunk of operating cost comes from the historical part certification regime ("aviation" parts requiring traceability documentation, enabling the vendor to shaft the customer). For example my exhaust nuts (12) are stainless steel castellated nuts, worth about 10p each. They sell for GBP 20 each... I can buy them mail order from the USA for $18 each which is better but still a 100x markup. If "homebuilt style" owner maintenance was permitted then much lower cost parts could be used.