Hello support (@Sushi_Support-Team) ,
I think MarginNote is an excellent tool for use in my academic work. Please forward my thanks to the developers for their continued commitment to making MarginNote a wonderful app to work with. It must be a huge job to do considering the number of suggestions for improvement from us all! 
I read many blogs and forums before deciding to purchase MarginNote. One thing that all the blogs and forums said about MarginNote was its " … lack of ability to play well with other apps". They were referring to MarginNote export which does not allow the work done in MarginNote to be shared with other apps. This is the same issue that was pointed out by @jprint here in item number 3.
Therefore, if a critical feature for improvement could be suggested it would be this one - to have MarginNote export more friendly with other apps.
What do you think?