Recently a PDF purporting to be an early play test version of the 6th edition rules for 40K was released online. The guys at Beasts of War posted a video looking at some of the, again rumoured, changes in the game and what they will mean in terms of how the game flows.
While I have no way of knowing if the PDF is legitimate or not, if it is it promises to really break open the gameplay in 40K and introduce a wide range of tactics and strategy into a game that has been fairly boring since about 3rd edition.
The main change is that the entire turn is shared with players alternating during phases in that turn. Your opponent moves and charges and then you get a chance to move and charge. Assaults are only resolved after movement which means that you have a chance to counter-charge your opponent.
During my last game of 5th ed. 40K I had a situation where Kevin’s Jump Troops leapt across the table and destroyed a unit of Ork Lootas. There really wasn’t a lot I could do under the 5th edition rules but the rumoured 6th edition rules give me a lot of options, keeping small flanking forces nearby, putting the unit in Overwatch, that would have not only kept them around but also made Kevin have to think about how he was going to deal with whatever counter-measures I had in place.
GW has made no comment on the rules but given the near universal acclaim these have received it really puts the company in an odd position if they are fake.
Update: It appears that I misread and/or misheard the discussion of the turn sequence in the 6th edition of the game. Sadly it really hasn’t changed that much since 5th ed.