So this is going to be a bit on the editorial side, and if you're in to that sort of thing, read on. I have had a few recent conversations concerning what the optimal game size is for a traditional one-on-one game of 40K. Now I'm going to come right out and say that I'm of the mindset that the game tends to play best anywhere from 1500 to 1850. I have a few reasons why I believe that to be true, allow me to plead my case.
The Case for 1500-1850
Difficult Choices
A large part of 40K is list building. Well, it's a large part of nearly every war game, and indeed collectible card games (CCG) as well. Much of one's time during their 40K lifespan will be dedicated to list building. Obviously these lists can take some pretty diverse forms from power gaming to fluffy theme affairs. The list is an art in and of itself. Some people see it as a magic recipe, that a good list will carry any player to victory. Even a relatively new player to 40K can typically see flaws in that logic, so I won't carry water for that insane notion here.
A very basic element of putting together a list is choosing what to put in that list, but even more importantly; what NOT to put it. The 1500 point list usually exemplifies this best. You have to make some very real and very difficult choices. Typically at 1500 you can do a little bit of spamming, stretching the strengths of an army, but you'll generally have to counter that by making large concessions elsewhere in your force organization.
I see these difficult choices, and this period of list building as a crucial step in the overall battle. In real life, pre-battle planning usually weighs pretty heavily towards determining the victor, and I believe 40K should be no different.
An Answer for Everything
To quote on oft-maligned political figure "You go to war with the army you have." The higher the point values of a game, the more likely you will be able to field a counter to a particular strategy or unit. I don't believe that friendly games should be played where I build a list specifically to defeat your army. That way madness lies. It will be a short path from friendship to complete douche-baggery.
If I'm building an all-comers list, which I typically sort of do, then at a higher point value, I'll have an answer for most any tactical problem I might face during a game. Where is the skill in that? I'm not testing my strategy or tactics nearly as much if I have to make do with less resources. I'm sure someone would argue "Well your opponent can do the same thing, so therefore you would cancel each other out and there IS some skill in overcoming that." Sure sure, but I like the idea that I might have to utilize a unit in a creative way that doesn't play to the particular strengths of that unit. If I build a huge army, I'll likely have plenty of anti-tank, so why would I bother to take melta bombs on a tactical sergeant? Well, if I was playing lower points values, and I didn't have just loads of anti-tank, I might be willing to spend a few points to allow my tactical squad to pick up a little slack. Could be fun.
The MOST Important Point: Imbalanced Scaling
This is REALLY where I want to make a point. Not all armies scale well. This isn't an opinion, it's fact. If you don't agree, then you're wrong and you'll just have to be satisfied with being wrong. That's a harsh thing to say, but there you have it.
I had a very difficult discussion with a friend concerning my unwillingness to play 2000 points. I explained the above reasons, but then this last point was apparently difficult for me to get across to him. I have a few examples of armies that fail to scale well, so let us begin with a major culprit:
GREY KNIGHTS!
Note that I didn't say "Daemon Hunters" because that would me Inquisition units, I have met multiple people that are interested in fielding Grey Knight only armies. These armies SUCK at scaling. One could argue that they suck pretty much completely, and I wouldn't totally disagree with you. For the time being, they suffer very badly at the hands of their outdated rules. There are other armies that suffer from some of the same problems that I'm going to mention here (*cough* Tau *cough* Necrons) so keep those in mind as well. Here are some issues:
1. Special Rules that no longer work.
This is a critical one. Many of the GK rules related to Demons, don't work as Demons have changed since the Daemon Hunter codex come out. These special rules are still accounted for in the points for the units, so you pay a premium for rules you can't use. That sticks.
2. Force Organization choices.
Many of the 5th edition codices out there have some ROCKING good choices in all of the force organization slots. Look at Imperial Guard! You can find good choices up and down the FO chart, and thus, regardless of the points value of a game, you'll be able to find something useful to put on the table.
Returning to our example of the GKs. They have HORRIBLE choices. They have one (1) fast attack choice. It's basically a slightly more expensive, non-scoring version of their one (1) troops choice that can deepstrike and have broken beacons. Hurray! The most popular list for the GK's these days include three Land Raiders, as they're needed to be used as transports for the army. So BANG goes your Heavy Support Choices... NO DREADS FOR YOU, naughty GK player! You're basically stuck with troops and elites. And you'd be hard pressed to find GK players that think their troops and termies are totally properly valued.
Remember, I don't just mean this happens to the GKs, because you don't have to look to hard to see this elsewhere.
My Metaphor for scaling issues
So let me put this into some silly terms. You and I are going to have a race. In this race we must select from some relatively similar cars. After selecting the car, we're each given a limited amount of money that we can spend on gas. You, however, are charged more per gallon than I am. In addition, my car is roughly 2 seconds a lap faster than yours. But your car comes with a kiddie seat.
If we were going to race, you had better hope it's a short one.
I'm paying a more real point-per-unit price, and I have special rules that make sense and work with the current core rules. You are paying more per unit, and you have outdated rules that may not, or flat-out do not help you.
This gives us the exponential problem of 40K. If you are paying more for less, than paying a lot more will still get you less, if not a lot less. There's no amount of water that you can pour into the bucket that will plug the hole in the bottom of the bucket.
I'm not saying that these scenarios are hopeless for those put at a disadvantage, I'm just saying that Lady Averages isn't really lifting her skirt for you. Sure, play 10 games of Grey Knights versus Space Wolves, and the GKs might just win one. I just wouldn't want to be the GK player for those ten games, is all I'm saying.
Wrapping it Up
I'm not completely opposed to larger games, but I think we need to stop this escalation trend I've spotted in the last two years. The norm should be 1500-1850, and the odd occasional game should be 2000+. And the only good reason to play below 1500 is for teaching someone to play, crazy scenario games, or alternate rules (Kill Teams, Killzone, etc). What do you think is a reasonable game size for just normal games?