Really? Which other countries make you register with their tax department to sell to their inhabitants? I'll admit to not having to deal with many, but all I did it was the recipients problem to pay taxes on goods they ordered from abroad. Or are you talking about B2B rather than B2C? I see that they have targeted the ebay/amazon style platforms particularly in that it is them responsible for the vat, rather than the real seller. In that case I expect people to keep selling to us, but won't a lot of websites need changing to say if you are from the EU it's one price but if from the UK it's now more?
And then we have some rather unscrupulous hauliers charging way more for parcels into the UK than the new changes to paperwork warrant.