I threw dice with the new book. Unlike 95% of the community, I didn't drop Mortarion on game one. I hit up an old buddy's Black Templar. My list was a little something like this -
Mortarion's Anvil - Battalion
Winged Demon Prince - 2x Claws, Warlord - Gloaming Bloat, Warp Hive, psychic power - Putrescent Vitality
Malignant Plague Caster - Gift of Plagues, Miasma of Pestilence
5 Deathshroud Terminators
2x5 Blightlord Terminators - Flail, Blight Launcher
Plague Surgeon - Fugaris' helm
Foul Blight Spawn - Revolting Stench Vats
Helbrute - Multi melta, missile launcher
Helbrute - Multi melta, fist, combi-bolter
2x5 Plague Marines - blight launcher
2x Pox Walker Blobs
2x Bloat Drones w/ Flesh Mowers
BLACK TEMPLARS at a Glance
Primaris Biker Chaplain
Grimaldus
Primaris Techmarine (master of the forge, relic of 4++ invuln for a turn)
Blob of Hammer/Shield Assault Terminators
Apothecary (WL trait for free revives)
Blob of storm shield vanguard vets w/ a few hammers and a Sword of Judgment
2x MM/bolter Venerable Dreads, Ironclad w/ Hurricane Bolter, 2x Hunter-killer missiles
3x Crusader Squads to babysit objectives
Suppressor Squad
2x Outrider Squads
IMPRESSIONS
OVERALL - This army is slow, durable, and requires careful deployment - unless you're deep-striking or coming in from strategic reserves, you're not going to go that far. We don't have a lot of shooting or long-range assets, so be prepared to protect those. Being tough doesn't mean you break cover and walk in the open, daring the enemy to attack you. 2+ saves like cover just like everyone else.
By Assets
Demon Prince - I realize claws are now AP-1; I realized this when I charged storm shield terminators. I'm lucky I'm not dead. The sword is 100% the way to go on these guys. Wings are expensive, but I like the FLY keyword.
Psychic Powers - Miasma's basically an auto-take. Gift of Plagues depends on your warlord traits, but debuff contagion auras (and Flash Outbreak) along with this are dumb. Gift of Plagues can do work even as turns tick over, since debuffs are great!
Blightlords - mine are modeled with axes. I am still reasonably pleased with axes - S6, AP-2 means I'm hitting on 3s and wounding on re-rolling 2s vs most infantry and swords are 3's and 3's. S6 also lets me grind at vehicles in a pinch. I'll see if I keep that opinion, but the flail and the blight launcher are obvious keeps. I'd considered a combi-weapon or two, but didn't miss it much - we're so slow that you might get one productive melta shot, or a turn or two of plasma plinking at best.
Deathshroud - If you're going to bring a brick of terminators and characters, you're bringing a unit of these. They're murder, though the spray pistols need contagions to kick in for that S3 to be meaningful. No one really wants to get close to them.
Pox Walkers - if you've got enough other threats out there, people probably aren't going to waste the volume of fire necessary to kill 15-20 of these guys off an objective. If you're going to tie up stuff, don't be like me and derp out and forget dreadnoughts with hurricane bolters can fire those in assault.
Plague Surgeon - take Fugaris' helm. That is all. Seriously.
Foul Blightspawn - take revolting stench vats. Seriously. A 6" no-charge bubble is a lot more user-friendly and harder to avoid than a 3" targeting "you fight last" power. The spray is a mop-up ability here.
Helbrutes - we get our big guns where we can. I think most of my lists will start with either a couple of these or a couple Blight Haulers. These things get terrifying if someone chips a wound off them; Fire Fever means I'm hitting on 2s (and possibly re-rolling 1s) then I'm wounding most armor on a 2 (and re-rolling 1s if wounded). I really don't care if I have to put a combi-bolter into an armored target for those bonuses. One of mine got popped early after whiffing, and another smoked the Ironclad, then almost beat a second dread to death (..before someone made a couple 6s to shrug).
Bloat Drones - Our book needs mobility badly - this is an option. Again, if I'm not taking Blight Haulers, I'm probably take a couple of these. The heavy blight launcher isn't bad per se, but the flesh mower is just terrifying. One guy tanked dreadnought multi-meltas (more luck than anything else) and then delayed them; another used the "eat guys for wounds" stratagem, and managed to do some solid work and last the game. Any sane opponent with guns is going to do their level best to murder these to deny you options.
Hilariously, bloat drones are allergic to AP-1 bolt guns, or 1d6 damage weapons.