The new release is mainly all about the new Remix decks which Native Instruments has actually trademarked. Meaning: It's kind of a big deal for them, but what does it give us users?
What the new Remix decks in Traktor Pro 2.5 basically does is take 4 ableton decks and put them direcly in to a deck Traktor. Switching all 4 decks in Traktor in to Remix decks will give you the ability to play 16 tracks at once and have 256 samples or loops at your fingertips.
You will be able to store each Remix deck as a "scene" or what NI calls a Remix Set (Also Trademarked) and quickly create a 64 (4x16) sample bank.
All in all this makes Traktor an alternative for Ableton users. What Traktor gives in adition to Ableton is offcause the native DJ experience and workflow. So in effect I believe that alot of Ableton users now will switch from Ableton and start performing in Traktor.
I guess the goal for Native Instruments is empower the DJ to be able to create remixes on the fly and have a tool and workflow that is both powerfull and user friendly. Together with the F1, I fermly believe that there is no other DJ software on the market delivering this much power.
There is alot of new adaptations under the hood with this release aswell. You can now change the quantization for the decks. This probably means that you're not locked in to 1:1, but can go further down into quantization to be able to say in time and beeing able to play with 16th notes. Looking forward to seeing this.
Also they've upgraded the beat detection feature. Though not as good as Ableton, Mixmeister or M-Audio Torq (which is able to handle songs of beat) it's getting closer. The tempo tap feature helps alot in these cases though and can help you stay on beat even if it changes. This is usefull in tracks that change beat. The new thing is that you will be able to go back to the previous stored tempo if the track is locked.
Read more about the new upgrade of Traktor Pro 2.5 at Native Instrument