can't get "create photos at points of view" to work. When I click "Create" button, a folder picker windows always comes up, and hitting "Select" just gets back to "create photos at points of view" window.

Are you really sure the images are not created in the folder you chose? Maybe the creation went so fast that you didn't see the progress message appear. If it's the case, I should probably display a message telling the process is finished.

the new "materials" function is greyed out on grouped objects, even if they are similar, and it's possible to change materials for them using multiple selection.

I didn't allow this kind of changes because I felt that in many cases, it would be too complicate for the end user to understand which material he's modifying. Note also that materials could have the same name from a model to an other but with different color or texture.