And on top of that, you can be audited by each EU country's tax authority as well... something I have not seen too many people worried about. I think it's an important thing that is being overlooked.
But other than that, there are other allowed bits of information to proof country of consumption, it's just going to be a pain to implement in your check-out process :-/
"Amazon do not abuse it, they just run shop from an EU country with low VAT rate (Luxembourg) last I checked."
They "abuse" it from the point of view from the countries where they don't pay the VAT.... f.e. the UK would like Amazon to pay VAT in the UK, and not in Luxembourg. So this new law is meant to prevent that, but at the same time waltz over small companies.
Actually, there is a lot of difference but not just because of the global lock to database lock transition. There is also a lot of work done on yield-before-lock: http://blog.serverdensity.com/goodbye-global-lock-mongodb-2-... And don't forget that replication also happens in a different database...