I think these guidelines are great. Just a couple thoughts:
I know there's only so much space in these guidelines (and in papers) but my two cents about the assumptions is that it isn't enough to mention the assumptions by name but to give a short description of what they imply in the context of the question being asked. E.g. Rather than 'we assumed the exclusion restriction' one would write, 'we assumed that the effect of the 162 SNPs in our analysis on CHD was only through their effect on education.' I think putting the assumptions in real-world terms makes it easier for non-MR people to understand what is being assumed and can even make it clearer for people who are familiar with the term 'exclusion restriction'. I advocate for this in non-MR studies as well.
I also agree with the point made by Prof Debbie Lawlor at the MR conference (if I understood correctly) about being clear that the effect should be interpreted as the effect of changing the exposure through genetic means. Although, this is captured, to a certain extent, by 16 c) which asks whether other interventions could have the same size effect.
Also, just a thought, are we at the point now where the guidelines should not just be, "State whether statistical code is publicly accessible and if so, where," but instead, "Make statistical code publicly accessible and indicate where." Of course, there may be special circumstances where it's not possible to share code, but otherwise, it is very easy for anyone to share their code now and it's an important part of transparency and reproducibility.
Thanks! Great work!