The real question is what isn't wrong with it.... On the technical side of things,
1., Performance is abysmal. The new Flickr immediately crashes my iPad and phone, and causes Firefox and Safari to hang and occasionally have to be force quit on my C2D Mac mini.
Can't comment on iPad performance, but it worked fine on my Mid-2007 Macbook C2D, works fine on Firefox and Chrome on my work PC, on Firefox and Safari on my early 2009 iMac, and on my Razr I.
2. Stats have been deleted? Every time I click on the link I get sent to an error page.
My stats are showing fine, either by going direct to the page as I sometimes do, or through navigating as normal from the main Flickr page or my Profile page.
3. The slide show system is now broken. All of my devices will only show each photo for around 0.5 seconds.
Again, I 've not had any issue with slideshows on any of the devices listed earlier. All working fine...
4. All of the EXIF data has been removed. When I was starting as a photographer I liked to look at others data to see how to set up my camera, now no one can do that.
Again, I can see all my EXIF data as before, including the copyright info and licence restrictions that I've set within the Camera to be added to every photo
5. All of my plugins are broken. Yahoo did a suberb job in giving a whole 0 minutes for developers to code for their new updated site..
Can't comment on that.
6. The guest pass feature appears to have been deleted.
Never used it myself, but it IS still referenced in the Help/FAQ section:
Help Section.
7. All of my collections that I meticulously maintained have been deleted against my wishes.
Again, all my sets and collections appear normally, untouched, and all the tags and location data is correct.
I'm glad you like it, you are just about the only person though... There is a comments/complaints thread on Flickr, that in the last about 16 hours has gotten around 10,000 complaints, versus what appears to be just a handful of compliments.
10,000 out of how many users? If people like it, do you expect them to post and "complain" about how they like it?
As others seem to access their info fine, could the issue be at YOUR end?