The screen size and resolution of the iPad mini 3 remains unchanged- 7.9'' and 1536 x 2048 pixels. It's not the thin, optically laminated, barely reflective screen of the iPad Air 2, instead its just the panel. This basically means that the iPad mini 3 isn't any thinner and in fact weighs the same too.
In fact this is a short run through of all the new features or changes: TouchID and Apple Pay, oh and how can we forget the model name as well. The 32 GB option has now been discontinued (which at least gives us cheaper 64 GB and 128 GB options).
For you camera enthusiasts, prepare to be disappointed as the camera department remains unchanged. The iPad mini 3 has the same 5 MP iSight camera and a HD FaceTime camera. In terms of connectivity, surprise surprise no change there either with no Cat.4 LTE or Wi-Fi 802.11ac. But considering that it's still running on the old Apple A7 chipset, its understandable.
The iPad mini 3 comes in 16 GB, 64 GB and 128 GB options for 400$, 500$ and 600$ respectively. LTE versions would set you back a further 130$. There's also a new Gold color scheme in addition to the Silver and Space Gray.