ESMA have published this paper which gives a cost benefit analysis of MiFID II.

The paper looks at the various aspects on MiFID II and how the different stakeholders will be impacted. Section 7 (page 382) looks at how MiFID II could hit those in the commodities markets, covering the reduced exemptions and position limits/reporting.

It is also worth noting the sections on Non Equities and OTFs in general.