Really the first rumors of what a Dark Angels codex might really start to look like. These couple bits talk of increased of chaplains and plasma cannon sponsons on tanks.

Please take these with the standard amount of salt.

via Stickmonkey
Next incarnation will see expanded use of chaplains. Rumor is they may be able to be taken in groups and assigned to lead troops, like wolf guard. If solo they stay elite slot, if Interrogator they are hq. Interesting to see if it pans out. No word on if/when Codex might be coming.

Another little very tenuous bit.
Heard this stuff elsewhere before, however coming thru a more trusted source now...
Rumor of plasma cannon sponsons on DA tanks. And a special Plasma main gun predator or vindicator...