Thanks for a ll the great feedback. I will have to write a bunch of issues over the next days and start working on them. Actually, I was hoping for about 5 upvotes and maybe two comments when I posted this on Hackernews, and the feedback is quite overwhelming.

Regarding selection of elements froma group, you can select individual elements with Ctrl + click. The selection process is a bit messy and I need a cleaner concept, but maybe for now this helps.