Viewing, zooming and commenting

After uploading a pdf file with spreads to the Cloud for a group of collaborators to check, they actually couldn't zoom in to read the text. At the end I had to send the file by email and got the comments by mail too, which is something I really want to avoid to achieve more effective workflow. I'd really appreciate if the zoom tool functioned properly and that the people I share the files with could mark and comment on individual spreads/pages. Even better if you could somehow mark/tick the comments that you've  dealt with to see which ones are solved and which are not.