So, let's go ahead and be real - marines kind of needed the Devastator Doctrine reeled in a little bit. Maybe more than a little bit. So, there are two things for folks to do -
1) Party! Especially if you're not a marine player.
2) Consider changes to your list, if you are a marine player.
I've always had a soft spot for the Iron Hands, and I've painted too many of them to want to sell anyway. So, time to actually figure out what's next -
Question 1 - What's the Nerf?
Question 2 - How does this change the army?
Question 3- What Can I Do To Mitigate it?
First up, the nerf itself - you're devastator doctrine turn 01. You change over to tactical doctrine on turn two, and you have the option to stay in tactical doctrine OR advance to the assault doctrine in turn 3. You are absolutely in the assault doctrine by turn 4, though. Marines also lost the stratagem to change the doctrine for their army, which only makes sense.
For Iron Hands, our bonus is two-fold - "move and shoot heavy weapons without penalty" and "re-roll ones if you stood still."
How does this change the army?
So, units that stood still and had heavy weapons basically didn't need captains, since you already had it. Additionally, remember that the first 1-2 points of AP are where you really make your money - the first point of AP essentially negates cover (if applicable) or really helps, and the second point of AP starts making high-rate-of-fire heavy weapons (IE - Thunderfire cannons, storm cannon arrays) much nastier.
You also had vehicles and/or dreadnoughts basically wandering around not caring about the number of heavy weapons they carried - move-and-shoot heavy weapons along with the fact that Iron Hand vehicles are basically full strength until at ~3 wounds is fun. (Well, unless you're the person that left them on four wounds, at which point you basically did nothing).
So, your heavy weapons aren't as mobile, and your stationary heavy weapons aren't as accurate. At a glance, here are some losers, in no particular order -
The pain, the pain!
Thunderfire Cannon - loses out on some accuracy, but BS2+ is still solid.
Dreadnoughts - outside of lascannons and missile launchers, most dreads need to move up to fire, so they lose mobility. Also the Leviathan dread in particular notices it, since AP-2 makes a big difference to vehicles.
Tanks without Power of the Machine Spirit - you lose out on some mobility, or at least you're back in the land of trading your move for -1 to your shots with your big guns. Looking at predators, razorbacks here, for example.
Flyers - You generally a lot of heavy weapons (if not exclusively heavy weapons), and generally have to move. Or, if applicable, you can hover and hope that no one takes the opportunity to tear you out of the sky. T7 doesn't like massed small arms fire.
Turn 2+ Deep Strikers w/ heavy weapons - drop devs and terminators notice it, but outside of grav cannons I'm not really sure what I'd want in a drop pod anyway.
Stalker Bolt Rifles - if you've got squads in the backfield holding objectives, they don't care. But if they move, it's a -1 to hit on a squad without a lot of shots.
Attack Bikes - you have good turn 1 mobility - not so much after that, at least not without losing accuracy on the guns. The heavy bolter bike doesn't care as much, but the multi-melta bike does.
Land Speeders - Eh, honestly, you were probably just hiding them the first turn and then moving into firing position. I'd feel this more if I wanted to try landspeeders more.
Devastators - They'll want a babysitter after turn 1 if you want re-rolls, and I feel like plasma cannons had a brief moment to be cool before this. Or at least not blow up as often.
Eliminators - let's be real, they were probably going to camp in cover the whole game and re-roll hits. Now they're just going to be in cover.
How do I mitigate this with stratagems?
There are a couple stratagems you want to be aware of when it comes to losing your dev doctrine.
Methodical Firepower - one unit's back in devastator doctrine. Pretty self-explanatory.
Big Guns Never Tire - one vehicle does not take the penalty for moving and firing heavy weapons. It's not additional AP, but if you have a lot of heavy weapons, well, it's worth it. (Hello, Stormhawk Interceptor...)
Wisdom of the Ancients - if you brought dreadnoughts, and your captain (if applicable) is elsewhere, it's a re-roll aura.
How do I mitigate this with particular units?
There are also a couple of units worth mentioning that boost ballistic skill -
Iron Father Feirros - BS2+ on a normally BS3+ model is basically the same as not taking the -1 to hit penalty.
Chaplains with Recitation of Focus - hey, it's +1 to hit, kinda like your iron father, and it's another application of it. Remember, Chaplain Dreadnoughts are real.
What does this mean for my list?
So, you get dev doctrine for a turn, and then you're down to one unit a turn getting it, and potentially one vehicle moving and shooting without taking a penalty. On the flip side, rapid fire weapons are going to enjoy bonus AP for a couple of turns - I wouldn't build around that as much as I'd be aware of the fact that my stalker bolt rifles and infantry-borne heavy weapons are losing mobility.
Here's a before-and-after of my IH Flyer list, and what it meant to me. I'm not claiming this list was perfect or anything, either. It's just an example -
BEFORE THE PAAAIN!
Iron Hand Battalion -
Chaplain Venerable Dreadnought (twin-las, dreadnought CCW, storm bolter)
Phobos Librarian (auto-medicae bionics, tenebrous curse, mind raid)
Invictor Warsuit (autocannon)
Invictor Warsuit (autocannon)
5 Infiltrators
5 Infiltrators
~7 Primaris marines (stalker bolt rifles, power sword on sarge)
3 Eliminators (3 bolt sniper rifles)
3 Eliminators (3 bolt sniper rifles)
3 Eliminators (3 bolt sniper rifles)
Iron Hand Spearhead
Primaris Lieutenant (power sword, pistol)
Thunderfire cannon
Thunderfire cannon
Thunderfire cannon
Flyer Wing
Stormhawk Interceptor (las-talon, 2 assault cannon, 2 heavy bolter)
Stormhawk Interceptor (las-talon, 2 assault cannon, 2 heavy bolter)
Stormhawk Interceptor (las-talon, 2 assault cannon, 2 heavy bolter)
The idea is that the invictors and infiltrators hold midfield objectives, and the flyers roll up to wreak havoc. Thunderfire cannon + Phobos Librarian can screw with the movement of up to three units. Lieutenant babysits the cannons. Flyers, well - it's a lotta guns, and you pretty much have to kill them to make them stop. CP generally went towards double-tapping the thunderfire cannons.
AFTER THE PAIN
Iron Hand Battalion -
Chaplain Venerable Dreadnought (twin-las, dreadnought CCW, storm bolter)
Phobos Librarian (auto-medicae bionics, tenebrous curse, mind raid)
Invictor Warsuit (flamer)
Invictor Warsuit (flamer)
5 Infiltrators
5 Infiltrators
~8 Primaris marines (stalker bolt rifles, power sword on sarge)
3 Eliminators (3 bolt sniper rifles)
3 Eliminators (3 bolt sniper rifles)
3 Eliminators (3 bolt sniper rifles)
Iron Hand Spearhead
Primaris Lieutenant (power sword, pistol)
Thunderfire cannon
Thunderfire cannon
Thunderfire cannon
Flyer Wing
Stormhawk Interceptor (las-talon, 2 assault cannon, 2 heavy bolter)
Stormhawk Interceptor (las-talon, 2 assault cannon, 2 heavy bolter)
Stormhawk Interceptor (las-talon, 2 assault cannon, 2 heavy bolter)
Not much changed, did it? Here's my logic -
Flyers - two of them will be accurate on turn two, one way or the other. If I still have all three on turn two, I'm in great shape and probably winning. The one that has to hit harder targets (or chew on a vehicle) gets the devastator doctrine, the other just gets to shoot at BS.
The Invictors dropped autocannons for flamers for two reasons. First, these things need to be disrupting the enemy by getting in their face, so while the autocannon's 48" range is awesome, I'm not going to get a lot of mileage out of that range after the second turn, and if I don't have flyers to use my stratagems on, well, I'm probably in a world of pain anyway. Or the invictors are punching something to death.
I don't mind having stalker rifles on the move with Recitation of Focus nearby, so they can stay.
Eliminators and Thunderfire cannons are just going to be a little less accurate, and that is what it is.
In Conclusion
In general, we got less accurate with some of the big guns. Very few things (like plasma cannons) took a major hit, and we have ways to mitigate the hit to accuracy. If you built around a lot of vehicles (like, a LOT, like razorback spam + land speeders or something) that move, you're definitely going to feel it.
