Two posts in one day? Shocking, I know, but bare with me. Gimmick lists are something I've been seeing a lot with the new Imperial Guard Codex. People will run them, and often claim that they're just as good as normal Combined Arms lists. I plan on discussing this issue in depth, but first, let's talk about what exactly I mean by "Gimmick Lists".
I consider a Gimmick List to be something that focuses heavily on one unit, or combination of units, to the exclusion of all others. Some examples are All Vets, No Tanks, Chimera Spam, Air Cav, and Conscript Press. I do NOT consider Gunline and Mech lists to be Gimmick Lists, as they tend more to be play styles, and can be carried out in a number of different ways.
Now, the general problem with these lists is that they do focus so heavily on one unit type or combo that they become very, very vulnerable to the counters an army can bring against that unit. It's not a problem as much at lower point value games, but when you get to 1500pts+, the enemy can bring enough tanks, guns, or very angry men with sharp objects to rip apart a Gimmick List with relative ease, especially compared to a balanced Combined Arms list, which can very very hard to crack.
Let's talk about each of those examples.
1. All Vets: What it says on the can. This list takes Veterans as only troop choice, usually with a CCS and either Chimeras or Valks tossed in. While this does mean you're packing a lot of SWs, it also means you've sacrificed HWs, and therefore an effective gunline. Vets CAN take HWs, but not in the numbers of a Platoons can, and it also means your SWs aren't being put to good use at close range. Also, any advantage in survivability that Grenadiers and Forward Sentries give you is nothing compared to the two Infantry Squads you could take for the same cost. Not only is that more wounds, but it's two targets, thus splitting the enemy fire and reducing it's effectiveness. Vet lists have a lot fewer units on the ground, and thus the enemy can concentrate fire on them more easily. That's why people use Chimeras, here, to give the Vets a little protection and to gelp them blitz the enemy. The downside is that this further reduces the number of troops you have, with you losing 1 Vet Squad for every two you have in a Chimera.
Recommended Point Levels: Vet armies work great at 500 or 750pts, but will struggle at 1000pts unless in Chimeras or Valks. Even adding those in will only extend their effectiveness to 1500pts, and which point you really get crushed under weight of numbers.
2. No Tanks: This means no Russes or Bassies. Some of the more diehard IG players will call that heresy, but it's not a bad tactic. Sentinels and Valks work pretty well up to a point. Valks and Vens do pack a punch, and Sents can be useful for playing merry hell in the enemy lines. This list also makes good use of HWs (hopefully), to help offset the lack of Armour. The downside is that you hav only one way of throwing out those High Str, good AP templates that almost all our tanks have, and that's the Demo Charge (which is unreliable at best). Russes DO have a purpose, and that is to be shot at with everything up to (and often including) Lascannons, shrug it all off, and blast something into paste. Sentinels are fragile as a wet tissue, and Valks and Vens aren't much better when it comes to armour. You take a substantial hit on the survive ability of your armour, as well as their effectiveness and ability to kill masses of troops.
Recommended Point Levels: Almost mandatory at 500pts, and works pretty well at 750 and 1000pts. They'll struggle against 1500pts, I find, when the other army is packing a lot of High Str weapons that can bring down the lighter non-tank vehicles. I would recommend this at 1000pts, max.
3. Chimera Spam: The idea here is to put all your infantry in Chimeras. Platoons, Vets, CCS, anything and everything that can take one, gets shoved in a Chimera. This is one of the three stronger Gimmick Lists. It can suffer from the lack of HWs, although Chimeras can help offset that with their turret weapons (keep in mind, through, moving 12in is in your best interest). This means that the enemy isn't as soft as one might like when your troops reach them, which is why Hull HFs are generally a good idea. It also suffers from the lack of men (every Chimera you take is one less Infantry Squad with a SW), but not to the extent that the Vets list does. It also means you have to get shot at by a LOT of weapons as you advance, since you've trimmed your army down and stuck them all in transports to make nice boxes for the enemy to shoot. Remember, too, that your Chimeras can explode, and kill a good portion of the squad inside before they ever fire a shot.
Just to be clear, this is different then Mechanized, as Mechanized will usually have Hellhounds, Valks, Sents, ect, tossed in. The Chimera Spam generally uses just Chimeras, with a handful of Russes backing them up.
Recommended Point Levels: Generally too expensive for 500 and 750pts, this list really becomes strong at 1000-1500pts. Higher then that, though, and your Chimeras won't be able to stand up to the volume of fire headed your way. Your infantry will be walking, and since there are less of them because you spent points on the Chimeras, they'll be cut down in short order.
4. Air Cav: Again another one of the stronger lists, Air Cav will consist of Platoons, Vets, and/or Stormies in Valks and Vendettas. This list packs a pretty big punch, is fast moving, and gan play havoc with Gunlines. They are VERY expensive though (in terms of $ and points), and are something of a Glass Cannon. If you get first turn and deploy well, you can cripple the enemy in the first or second turn, then drop your troops off to finish the job. Lose first turn, or deploy poorly, and you'll get shredded. It also has the downside of needing to take Squadrons for it to work. This is okay at the lower point levels, but can badly hurt your ability to kill multiple targets at larger point levels. You either have to fire all your Vendettas at a single tank, and all your Valks at a single infantry unit, or you mix the squadrons, and waste the shots from the Vens when shooting at infantry, or the Valks when shooting at tanks. The situation remedies somewhat when you get boots on the ground, but it still limits your ability to punish the enemy army before you dump troops on them.
Recommended Point Levels: Too expensive for 500 and 750, the Air Cav list comes into it's own at 1000-1500pts. Even at 1500, though you start to feel the Squadron Pain, and at 2000pts, it hamstrings you so much that I would almost consider it nonviable.
5. Conscript Press: Usually used with Chenkov, this army relies on the tried and true Soviet tactic of "They can't shoot back if they're covered in corpses". Usually combined with Chenkov, this player will send waves of Conscripts at you, usually backed by HWs and a few Russes. It's strong in that it will choke the enemy with targets and CC units, while still allowing you to pound them at range, but it has the downside of losing LOTS of men, and reducing your fire output for the meat shield. It also means you'll probably be shooting through your own men, giving the enemy a cover save, and has the risk of CC actually blocking LOS quite badly. A Commissar Lord is also a mandatory unit for this list, and will die if you wipe out the Conscripts without removing him first. It's generally better to take Combined platoons, where you can hav SWs and Power Fists, as well as cheap Commissars. The unit also has better WS, which is nice against Tau.
Recommended Point Levels: Hard to do at 500pts, but good from 750-1000, and not bad at 1500pts, although that's where the big nasty things like LR Crusaders, Carnifexes, and huge masses of Orks tend to show up and pulp your screen on the way to your HW teams. Still somewhat viable at 2000pts, just for the sheer number of Conscripts you can take, but don't expect them to last long.