Right now I'm thinking about deployment strategies. Warhammer 40,000 is interesting in that the game is much like the head-punching competition in Atanarjuat The Fast Runner, in that the competitors politely take turns punching each other in the temple. You really want to get that knock-out blow, disabling an opponent's ability to punch back, and knocking them out of the game entirely if possible. And because everything fails on a roll of 1 on the D6 being rolled, there's always a chance that your perfect strategy will miss completely, and a decent chance it won't hit anywhere near as hard as you want. So there's a strong element of friction mixed (wounds/hull points) into the Warhammer 40,000 shock (kill units, wreck or explode vehicles) and awe (failed morale/pinning).
It seems to me that Warhammer 40,000 is much like Rock-Scissors-Paper, but in the sense that Rock-Scissors-Paper is a continuum between two extremes (Null-Deploy and Castle) and how Null-Deploy beats a Hybrid of the two, Hybrid beats Castle, and Castle beats Null-Deploy, more or less. 'Castling' means, setting up an army so that the work-horse units survive the initial alpha-strike of a null-deploy army.
Now an interesting part of this whole business is that Warhammer 40,000 is unlike Rock-Scissors-Paper in that Castle-vs-Castle is not a straight tie. Some Castles are simply better than other Castles, and even some Hybrids. Think of it like there being a rating to the three basic strategies, in that their ability to score and their balance of power, flexibility, and redundancy in addressing opposing armies is such that there's a rating that causes some instances of a single type of strategy to have an advantage over other instance. Rock (2) will beat Rock (1), and Rock (3) will beat Paper (1) even though Paper (1) will beat Rock (3). Furthermore remember that Warhammer 40,000 is about throwing out a proposition, a particular strategy, and waiting to see if your opponent has the right answer to it. And by 'right answer' I mean does the answer they give pay off, as their answer might be high risk as well as low risk, in which case that reward had better be commensurate with the risk otherwise it's not going to be as good an answer.
I think that's the part that frustrates many people that begin 40k and get a feel for what the Internet likes to call the 'meta,' and copies down the lists currently winning tournaments as if they win tournaments by dint of being the right army rather than being the right army and being played right by an experienced player with an extremely good grasp of the game. Not to say I'm one. I'm working it out here, out loud so to speak.
Of course there's going to be ways that a Strategy (x+1) will fail against a Strategy (x), such as the player taking their resources, their units, and mis-deploying them such that they're not going to be playing a Strategy (x+1) but in fact a Strategy (x-1). I'm certainly guilty of making a plan, building an army, and then throwing it all away because I give into doubt in the face of the enemy, particularly one I wasn't thinking about in too much detail prior to deciding on a particular Strategy to play.
Consider, for example, a Castle against a Null-Deploy list involving a Drop Pod Assault. That means that half, rounding up, of the Drop Pods in that army will be deployed with a first-strike capability on the first turn of the game. Other armies can accomplish this sort of thing without Drop Pods, such as a Raven Guard Talon Strike Force, or a Black Legion Speartip. But those armies are going to do it without the Drop Pods that will come free in a Gladius Strike Force. Those Drop Pods not only make the deep strikes slightly more reliable, but they will function as heavily armoured gun turrets when they're down. Each Drop Pod can be three units if they're transporting a unit that has used the Combat Squads rule to split into two. That makes for a certain 'target saturation' with the goal being that there will be more targets available than the enemy can engage. When there are more targets than can be easily engaged, suddenly a bad round of shooting means that another unit survives the turn and can re-engage. It also means that it can engage more targets, lending out that Storm Bolter on the Drop Pod to pick off stray survivors, or plink off unit specialists, or another hull point off a light vehicle.
While the other half of the Drop Pods will be in reserve, that does not necessarily mean that they have to be occupied, so you can buy Drop Pods for units like Devastators and set them up while their free Drop Pods sit in reserves so that the Space Marine player can front-load the 1st turn assault with more Drop Pods and more units. It makes for a very good Hybrid force.
If I'm going to beat such a force, then I need to keep in mind not only the optimum mix of wargear, units, and psychic powers to engage and destroy my enemy, then I need to think about the different ways in which I can deploy that army to engage the Strategy my opponent will play. For example, in my last game I was expecting to take Gladius or Talon Strike Force to the face where lots of infantry would come pouring out of the Drop Pods with Flamers to try and negate my enhanced cover saves, or try to land Vanguard Veterans from a Shadowstrike Kill Team to beat my Daemon Prince into a paste with Thunder Hammers. Instead I faced an ungainly Salamanders/Blood Angel alliance with no detachment bonuses that proceeded to murder me with a host of Dreadnoughts, and mop me up with some mechanized infantry.
I believe that I mis-deployed, leaving Terminators with Chain Fists and Raptors with Melta Guns and Melta Bombs in reserve, and by leaving my Havocs with Autocannons out unsupported on my flanks where they covered the objectives nicely, but were exposed to the template weapons I should have been expecting. I played a weak Hybrid against a strong Hybrid. I feel that if I had played a Castle and deployed my Havocs inside of my defensive perimeter of Rhinos along with counter-charge forces of Terminators, Raptors, and my Daemon Prince then I would have had a much better chance. Typically such a Hybrid would have beaten my Castle except that it wasn't particularly high power - Frag Cannons are horrific against nearby infantry, even Space Marines, but they're relatively overkill against a Rhino, and even AV13 Furiosos are easily put down when subjected to Melta or Armourbane weaponry. It was kind of stupid of me, I think, to spend points on Terminator assault wargear to leave them where they risked missing the action entirely, especially since they were equipped to engage armoured Drop Pods and Dreadnoughts, as well as do a number on any Space Marines happening by. As it turned out they managed to massacre one squad and then died as that squad ran away and left them high and dry in front of enemy Plasma Cannons. Dropping them in front of the Plasma Cannons was also a bad idea...
Of course, if I had taken those Melta Guns in the Chaos Space Marine squads like I had thought I should before settling on the Plasma Pistols on my Aspiring Champion models, I think they still would have gotten massacred by the first shots from the Dreadnoughts because they weren't protected by the Rhinos. Had they been protected from the Dreadnoughts' crushing first strike with S6 Rending Assault 2 templates they could have replied by taking out Drop Pods and Dreadnoughts alike, but if my opponents had not taken Dreadnoughts then the Melta Guns would have been relatively ineffective against infantry (although still good against Drop Pods, leaving me with the quandary of trying for a single-shot on the Pod or 8 boltgun shots on the infantry, or five Bolt Pistol shots and a charge, followed by 8 CCW attacks with Hatred and 4 PW attacks with Hatred...) or simply being out of range if my opponents had decided to castle against any Raptor or Terminator reserves I was planning.
Now I don't think Space Marines make a good Castle unless they go heavily into a Gladius with its free Razorbacks/Rhinos and that they're going to make a better Hybrid by doing like my opponents did. While Razorbacks and Rhinos are nice, there is not going to be much to address my backfield while engaging objectives except for any expensive long-ranged weapons on Devastators or Razorbacks, or Predators and Whirlwinds brought as Auxiliary. Which I'd imagine someone will try some day. Which is why I suppose I was so enthusiastic about the Raptors and Terminators, because I can use them to re-direct force around the board, but the Terminators were out-fitted as counter-assault and should have been used as such. Likewise, having the Raptors able to explode the Drop Pods would have, I think, been more effective than hoping Rhino rams and Krak grenades would have eventually taken them out once my Chaos Space Marines were done tangling with their passengers.