Chief Librarian Tigurius hasn't changed at all, as far as I can see. He still is a level 3 psyker that can re-roll when determining psychic powers, psychic tests, and reserve rolls. His Storm of Fire Warlord Trait got a bit better. Tigurius is still an excellent support character, and arguably the best Space Marine psyker.
Chaplain Cassius hasn't changed at all.
|My Executioners Telion, now relegated to being a normal Scout Sergeant. Still a cool model, though.|
Sergeant Telion gained a wound and is now an HQ choice, though he can only join Scout squads. Otherwise, his rules are all the same. He did gain the excellent Storm of Fire Warlord Trait. Telion is now a cheap, useful HQ choice. He won't do that much, but he's a cheap way to fill your HQ requirement.
Sergeant Chronus also became an HQ choice and gained an extra wound, but otherwise his rules are unchanged. He doesn't have a Warlord Trait, but his tank becomes a Character so he can be your Warlord.
Kor'sarro Khan is still a strong character. His points cost stayed the same, and his Warlord Trait stayed Champion of Humanity (which is now a Leadership re-roll bubble). However, his Master of the Hunt rule now gives him D3 extra victory points for killing the enemy warlord in a challenge as well as giving bikes and units in Rhinos and Razorbacks (but no longer Land Raiders) Scout. Khan is a decent combat character that really buffs his army, and is a very strong choice for any White Scars army.
Vulkan He'stan hasn't changed, but his Iron Resolve grants him Feel No Pain, making him even more resilient. Vulkan is a strong close-ranged character, and granting all of your melta weapons master-crafted is huge. He still grants this benefit to all the units in your detachment, not just units with Chapter Tactics.
Shadow Captain Shrike hasn't changed at all. He can still only join jump pack infantry before deployment, which I assume will be FAQed to give the unit he joins Infiltrate as well, since right now it means he can only infiltrate alone and that is obviously not the intent.
Captain Lysander has changed in some subtle ways. He switched the pretty useless Champion of Humanity Warlord Trait for Iron Resolve, further increasing his already legendary durability. The Fist of Dorn is no longer a flat S10, but rather +6 S. This makes little difference in most circumstances, but it does mean that he's now susceptible to various maledictions that can decrease his Strength.
Pedro Kantor is very similar to his previous incarnation, but two changes have greatly increased his poor durability. First, he finally got artificer armor, which makes complete sense. Second, his Iron Resolve Warlord Trait gives him Feel No Pain. In the past, he was a strong support character but died as soon as he engaged the enemy. Now he should be able to take on many combatants, though he's still not amazing in assault.
High Marshal Helbrecht really hasn't changed beyond The Imperium's Sword being active all game now. He still is a decent fighter in close-combat, with the ability to make the rest of your army much better at assaulting for one turn by giving it Hatred and Fleet. A very solid choice for Black Templars.
|Sorry Black Templar players, this is the closest thing to an Emperor's Champion that I've painted.|
The Emperor's Champion got a bit better, as both of his stances are now active all of the time. Therefore, he always had +2 S from the Black Sword (previously only available in challenges and no longer hindered by Unwieldy and Two Handed) and still re-rolls all failed to hit and to wound rolls in challenges, as well as causing Instant Death on a 6. All in all, he's a much better fighter in this codex, though he'll still struggle against most combat oriented characters (but he could get lucky with Instant Death). He will, however, slice apart enemy unit champions and support characters without any problems. For his price, he's definitely worth it, and he won't hamstring your army.
Chaplain Grimaldus received a healthy points drop (though his Servitors cost more), and is still as tough as ever. He still gives every unit within 6" Zealot, but his Cenobyte Servitors now grant Feel No Pain to every unit within 6". This gives him a fairly large Feel No Pain bubble, reminiscent of the old Sanguinary Priests. You can either take him as a very tough Chaplain to join another unit or run him with Servitors as a support unit. Either path seems quite viable now, and he will serve as a lynchpin for Black Templar infantry armies (the Black Tide, I believe they call them).