Simulated Knave wrote:
"don't change the current list"... was in evidence in the ground-pounding marine thread, though.
Fortis weighs in asking why marines on the ground have to be a competitive choice.
Rug "disagrees with the basic premise"
Hena claims variously that such lists work just fine and that thus the list is fine.
dptdexys objects because it will make bomber lists unviable.
You claim that the existing C:A list can make lists that work on the ground.
Mephiston claims that a ground list with marines can be done, but will be hard and unforgiving (and thus implicitly claims that that's OK).
Honda agrees with Rug.
There's a few people who are kind of neutral about the whole thing (TRC and Frogbear), whether through not feeling the need is quite pressing (though agreeing it's there), through not being sure either way, or through feeling the best way to deal with it is variants. And there's a few in favor (E&C, GlynG and Morgan Vening spring to mind). But there wasn't the sort of support for the idea that would seem necessary to change the basic SM list. Indeed, there's a not-insignificant number of those above who claimed that the idea of a ground-based Space Marine army was wrong on the face of it.
On the "ground pounders can work" side, that assertion is nearly always in the context of someone claiming that they are impossible. A refutation of the idea that mud marines are impossible is not the same as claiming that everything is hunky-dory. I am pretty sure everyone agrees that a ground force has drawbacks and restrictions. There are almost invariably a number of caveats about how to make it work. The net of all the commentary is really more that an SM list does not have to be all-air-assault/warhound to be competitive than an assertion that pure ground forces work just fine.
There are basically 3 factors that are included in every SM ground list that I've seen anyone post with the claim that it is competitive:
1) High activation count. Usually, this is achieved by 2-4 cheap fast attack formations and 1-2 cheap Tbolt formations.
2) Deepstrike is still present but in a more limited form. This might be limited to a single Thawk or by the use of Terminators. It's just not the typical multi-Thawk. (And a Termie formation ~350 points does a better job of preserving activation count than a loaded Thawk, so it goes well with the first point.)
3) Use of Razorbacks to min-max transports. They are the most cost-effective ground SM unit and they allow the extra transport capacity to keep formations mobile. Pretty much any infantry formation has an odd number.
Ground marines can work. They are restricted to a set of configurations defined by those traits and are relatively unforgiving (i.e. not strong, just workable). However, it's more flexible than it often gets credit for.
So, I agree with your perception that there is not the will to change the core list. Between the unacknowledged flexibility and the problematic nature of diverging from the "official" SG rules, I think it's probably better to make any major changes as a variant list rather than attempting an extensive revision.
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As far as "don't duplicate an existing list" I think that's pretty obvious. If you're duplicating an existing list, there's not really a point. You also want to avoid the "like that... only better" army list creep (again, an obvious consideration).
A list that's a little bit cheaper than another due to an inefficient build in the comparison list is probably not an issue. The problems come in when things that make the new list a little bit cheaper can completely take over and introduce a much larger effective point discrepancy.
To use an example, the early Apocrypha draft with a 250 point Tac formation was probably going to be a problem. The internal balance issues cascade to other formations. For example, a Tactical formation at that cost suddenly looks a lot better than fast attack formations at 200 - lots more durability, actual ranged firepower, similar speed on a double, better assault, shorter assault range when on the ground (but at that price, the risk of leaving them loaded is lessened, so maybe not that much shorter). The same kind of comparison applies to 225 point Devastator formations versus fast attack options.
If you look at a "normal" ground pounder list built with the criteria above, most have ~2 Tac/Dev formations. That's a 75-100 discount over Codex. Use that discount to upgrade the fast attack formations to troop formations and now you are looking at a far greater point discrepancy between a Codex build and the Apocrypha build - 4-5 troop formations, adding up to a ~200 point difference between Codex and Apocrypha.
That's definitely "like that... only quite a bit better" territory. Maybe the original build really is off by that much. Maybe not. In any case, that's big enough to trip warning bells and warrant serious consideration.