Your PC group has (that I'm aware of) used three primary means of travel/navigation:
1) Hoofing it manually
2) Phantom Steed Ritual
3) The flying tower that is sort of their analogue to the X-Men's Blackbird
Correct - though I hadn't thought of the Blackbird comparison before now. (The player of the Chan/Corellon-devotee chaos mage really wanted it, so I stuck it in the Glacial Rift, frozen in an icicle, as the retconned mode of arrival for the Storm Giant prisoner - who in my version of G2 was the crazed prophet of the Crushing Wave.)
The implications of 1-3 have had implications on your players' action declarations that span that tactical <==> operational <==> strategic continuum, right? I'm thinking of things like "go here and do this because of n (related to their ability to deploy or not deploy a resource) versus go there" or "provide air support for the guy on the flying carpet or the fighter in the middle of the army of bad guys" or "fly the tower into the entropic hole in the Abyss and stop it from sealing (or something like that...I can't recall exactly)".
Yes.
Phantom Steeds have been their default since mid-Paragon (when flying steeds became fairly reliably obtainable). This does structure where they go in the fiction, and the minion-esque nature of the steeds matters when combat breaks out (always a risk in D&D!).
The Tower didn't dramatically change these transport options, but did change the interface between transport and combat: instead of combat being about dismounting Phantom Steeds or trying to recover from having them "popped", it provided a fully operational, mobile firing platform with its own additional aerial support in the form of flying carpet plus jumping fighter.
If the PCs lose access to those resources due to fallout in the fiction (perhaps failure in a Skill Challenge), suddenly the scope of their tactical <==> operational <==> strategic continuum narrows.
The Tower couldn't fit through the portal they used to escape the Demonweb Pits, so they're back to Phantom Steed plus teleportation/portal rituals.
This may affect their ability to smoothly escape from Thanatos now that they have killed Orcus.
Hopefully that better reveals where I'm coming from, and you can tell me if we agree or disagree.
I'm not 100% sure what the actual topic of agreement or disagreement is, but here're some thoughts.
4e does involve strategic resources (eg Phantom Steeds, Thundercloud Towers) that can impact on operational/tactical matters in interesting and non-uniform ways. I think that's a point of agreement.
The players access to these (via their PCs) can be affected by action resolution within the relatively uniform, level-scaling device of the 4e skill challenge or 4e combat. I think that's another point of agreement.
Hence, outcomes in the operational/tactical space can feed back into the strategic space, again in interesting and non-uniform ways. I think that's a third point of agreement.
I suspect that [MENTION=6787650]Hemlock[/MENTION] would probably be happy to agree with all this too.
I think that one point Hemlock wanted to make was that a system of scaling environmental challenges (eg Cave Slime) makes a type of GM laziness especially easy, of not changing the overall
structure or deep nature of the game as the PCs level, instead just amping up the numbers and adding superficial descriptions (Astral Teflon Slime, Utra-violet Slime, etc) while leaving the basic dynamics of play unchanged.
I agree with Hemlock that Cave Slime and its relatives among the 4e system elements do lend themselves to this sort of laziness. I point to the HPE modules as evidence of this.
I think that 3E is equally amenable to this sort of laziness. I don't know a wide range of 3E modules as well, but having looked through Heart of Nightfang Spire and Expedition to the Demonweb Pits I'll point to them as instances of much the same sort of laziness in 3E. However, this is not necessarily a counterexampe to Hemlock's conjecture because 3E is ultimately a scaling, subjective system that hides that fact behind some purely notional simulationist labels like "natural armour bonus", "deflection bonus", "luck bonus" etc.
When I think of Rolemaster modules, they do have a tendency to emphasise the strategic and operational much more than the WotC 4e or 3E modules that I know, but I'm not sure if this is a result of design pressure emanating from "objective" DCs, or rather evidence of the preferences of the designers who wrote them (who, perhaps due to a common cause, maybe related to wargaming/boardgaming backgrounds?, also preferred "objective" DCs).
So I'm on the fence about Hemlock's conjecture. But I do agree with you (a fourth point of agreement, I think) that subjective DCs don't
force towards the sort of lazy design that Hemlock commented on. They may not even push towards it -
being amenable to isn't (either in semantics or in the real world) equivalent to
pushes towards.
A final thought for yet another rambling post (it's the middle of the night Melbourne time, why am I not in bed?): in AD&D campaigns the lazy design option tends to break down around 10th level (you've gone through all the basic humanoids, the ogres, trolls and most of the giants). You can broaden out a bit (look at how the D-series tries to do this - I am assuming that Hemlock would agree with this as an instance of broadening out to the operational and strategic), but I reckon many AD&D campaigns just fell apart at this point precisely because there was no material left to feed the lazy approach.
4e doesn't strike me as adding anything to this AD&D treadmill (for better
or worse) accept another 20 levels of it if that's all a GM and/or his/her table can come up with.
But, again, to
facilitate isn't to
force or even to
push.