It's ridiculous how the Facebook app, that is to 90% an app wrapping a web browser (you can compare the similarities at
http://touch.facebook.com yourself), can still have so many bugs.
For example, if I browse photos on Facebook for iPad, I can only "like" or comment the first one. After that, I need to exit the photo viewer, and re-open it again. It's also unstable when viewing photos in the first place. Sometimes it just crashes. Also, no timeline, and missing tons of Facebook features on the website. Not sure you can even remove friends from the app, or subscribe to people, or arrange friend lists... It isn't even translated properly - the localized version I use is a mix of my native language and English.
In short, an utterly horrible app for having Facebook's resources. Companies with five iOS developers have done better than them.
Retina support is far from the greatest feature it's missing.