Agreed accounting/payment processing is a crazy time sink. On the other hand, I'm not aware of any on-line payment service or marketplace site that could even support all the fundamental requirements for a lot of start-up business models to comply with the new rules right now without doing a significant degree of additional integration or customisation work anyway.
For example, it's all very well having the payment service work out the actual VAT and do the invoicing, but under existing consumer protection laws in various EU states you still have to show the tax-inclusive price throughout. That immediately means you can no longer display a static price on your web site, if you add VAT at the appropriate local rate to a fixed base price rather than having a fixed total price paid by the customer and then taking a different VAT hit internally depending on where each customer is.
For example, it's all very well having the payment service work out the actual VAT and do the invoicing, but under existing consumer protection laws in various EU states you still have to show the tax-inclusive price throughout. That immediately means you can no longer display a static price on your web site, if you add VAT at the appropriate local rate to a fixed base price rather than having a fixed total price paid by the customer and then taking a different VAT hit internally depending on where each customer is.