European markets are unusual in that their evolution is significantly guided by their regulatory bodies. MiFID - the Markets in Financial Instruments Directive - is only the most prominent of a number of directives that express this distinctive 'euro-approach': describe the trading environment as it 'should' be, and then legislate to make it so.
The problem is the gap between 'should' and 'is'. MiFID has given us a delightful picture of a European trading environment characterised by freedom, transparency and healthy competition. Back here in the real world, we're addressing fragmentation - which even has its own index - and the beginnings of consolidation. Competition has led us into darkness, while transparency is less a matter of going into the light (and thus losing exposure to all that dark liquidity) and more an obligation to plug in complex solutions to achieve and measure effective execution.
As technology outstrips oversight, the regulatory approach can seem not to have adapted to the new reality: compliance may be much tougher, but the requirement hasn't changed. And as we struggle to adapt to a world of unintended consequences, new regulatory initiatives continue to pit 'should' against 'is'.