Hey Ydars, what is this "other thread" you are talking about?
Anyway, let's try to address a specific example within the context of 4E.
Let's assume I have a map that allows the PC's free choice of entrance to the dungeon, and multiple ways to get down to the second level from the first. Furthermore, I have developed the levels to provide a series independent "delves" or "lairs" with sufficient empty space and room to wander so as to support credulity. Furthermore, the players can gather various rumors in town and choose to follow leads, or just head to the dungeon and explore.
Level 1 is therefore broken down into Lair 1-A, 1-B, 1-C, 1-D, 1-E; level 2 is broken down into 2-A, 2-B, 2-c, etc. You get the point. Let's say on level 1, the 5 lairs are The Bandit Hideout, the Kobold Dragon Worshippers, the Mutant Goblin Alchemists, Vermin, and The Hidden Tomb. Each one of these delves is designed to be 3-4 encounters; if you throw in quest XP and a skill challenge or two, the PC's should be in a position to level up after clearing 3 of the lairs. Likewise, the encounters would range from 'easy' to 'hard' in 4E terms, meaning they could be anywhere from the same level as the group up to 4 levels higher in XP/encounter design terms.
I would say, so far so good. The players can choose where to go, what to fight, when to go down to the second level, etc.
However, there are potential problems when you add the parcel system to the mix and when you consider the nature of 4E experience. With the parcel system, it's expected that you'd spread the level 1 parcels out amongst the first three lairs the players cleared, so they get the requisite wealth at the same time they leveled.
So far I've seen a few "solutions":
1. It's All Good
Ditch the parcel system and don't sweat the experience grinding; if the players attempt to be completists and clear the whole level (all 5 lairs), so what? Evenly spread out treasure (even if it's more than the 1st level parcels) and let them beat the snot out of whatever they want.
2. Scale Accordingly
Some have suggested, once the group levels up, the remaining lairs get adjusted slightly to be level 2 encounters (easy enough to do in 4E) and you start grabbing the level 2 parcels. Must... maintain... balance...
3. Remove XP Grinding Options
In this approach, the areas of the dungeon that the players ignored (and are now "easy") change due to other influences; rival NPC's clear them out; dangerous monsters from below come up and lay the smack; the PC's efforts on other parts of the lair have convinced them to leave; etc. The gentle XP curve in 4E makes it too fun and profitable to wail on weak monsters to keep this option around.
I'm sorely tempted to go with the # 1 option myself; I don't like the heavy-handed approach of # 3 (despite me championing it at times), and I certainly don't like option #2; I hate it when the the town guards are level 3 when the party is level 1, and suddenly they're level 6 when the party is level 3; the group should be able to make progress against other elements of the setting.
Oh, I did go back and read that 'fetishization of balance' article - it seems completely off the mark. The main point of the article seems to argue that you should balance the encounters against the current power level of the party, and not against an arbitray CR baseline. Yeah, that's option #2 above: if the party is suddenly more powerful, SURPRISE, everything starts scaling! Level 1 Kobold encounters become tougher all of a sudden! BLECH. That is the complete opposite of making an internally-consistent sandbox...