So we've all heard that GW has confirmed Templars are indeed getting their own codex in the future. And while there are rumors that they'll be coming out in December, those are really not all that likely. But here are some new rumors that might be:
via a good anonymous source on Faeit 212
In so far as Black Templar: They are getting a full book not a supplement. The direction of the book is on "crusades," and differentiating the Black Templar when they persecute Xenos as opposed to when they put the Witch to the sword.
They are seeing a lot of changes from their previous incarnation, and are no longer a shooting army (despite the intention of the previous book, they were received as a shooting army).
The army will have a "knights in space" kind of feel with wargear being a very big importance for the characters, and vows similar to old bretonians. The struggle there is with book keeping, but it is a pretty cool concept.
Crusade squads with their hybrid neophyte and space marine combinations are gone. Which will probably anger a lot of people without pleasing any (since in the past you could just take 0 neophytes so in essence this is just removing choices), but take it for what it's worth.
The whole "move after taking casualties" thing is gone and has been replaced with something more similar to battle trance (but less swift, and more assault oriented).
Templar point costs are down even from those of dark angels, and are designed to be balanced by their point cost, but also deliver the feeling that this is a "crusade army" that has never really felt the yoke of the codex astartes, and thus has huge companies of marines.