The rulebook FAQ is up, having a quick read through it now and one thing jumps out at me straight away - GW have gotten rid of the wound allocation shenenigans with regards to units of characters, you now have to resolve the look out sir! against the model in the unit closest to the character. No more bouncing wounds around the unit.
Flying MCs lose hard to hit. Makes sense and everyone has been playing this way anyway.
Zooming flyers moving at cruising speed move between 18.1 and 36 inches. again the only sensible way to play it.
Paladins, Wolf Guard, Nobs and Crisis Shas'vre are only characters when leading a squad. Big hit there to wound allocation as well.
Weapons that hit automatically still do so even if fired as a snap shot.
Death rays cannot hit fliers. big hit to the necron flyer wing.
Ignores armour saves means exactly that, boneswords, Tycho and Straken get a boost.
No overflow of wounds to the squad if you crush a character in close combat.
Fliers move at the exact speed in inches they did in the previous turn if they suffer from locked velocity.
Aegis Lines must be deployed as a continuous chain.
Grav chute insertion has been fixed to work in the movement phase.
Commissars will no longer shoot Calgar, only the highest Ld IG model.
Leman Russ' are heavy vehicles. Very slow now. The Ordance rules will override the rules for firing weapons while counting as stationary so I don't see too much of a benefit from this.
Allied ICs cannot use their Ld to pass an order, or gain any benefit from it.
Overall it makes sense, I haven't read through any of the others yet, but it looks promising.