This is the latest in the rumorsphere floating around for the Grey Knights. Whether the codex is on time or not for April, it is still probably the next codex as playtesting seems to be done.
And just a side note, I did hear that we are about to get a solid release date for the Blood Angels Furioso and Stormraven release. Thin rumors have it at the end of this month on the 29th, however I am figuring that is premature and that we will see them near the beginning of February.
Back to Grey Knights. Remember that everything you read should be taken with a grain of salt.
This from Tasty Taste on Blood of Kittens
The playtesting phase is done for the GKs
The MC Grey Knight has taken the slot away from what was originally given to Penitent Engines. The MC will be an Elite slot that is already becoming quite crowded with units. GK will be the Special Characters codex look for over 10 new special characters to play with at least 1/4 being inquisitorial in nature.
Assume any special powers (not USRs) are psychic powers instead. As an example, if you have Land Raider and it is immune to something it will be a psychic power (not wargear) same goes for Special Character powers. The ability to raise AV is almost certainly out of the codex or at the very least regulated to transports only. The Stormraven is currently still the only Fast Attack unit in the codex. The ability for GKs to teleport once per game is for basic GKs only not for terminators. Don’t believe any stats for the incinerator it is the one major piece of wargear that is still being debated. The special character that makes terminators cheaper can only make one squad cheaper think Tau honor guard.