Shin Okada
Explorer
As a rough example, there was a Living Greyhawk adventure back in 3.5e where the point was to get the unconscious King away from the people who were trying to take over the kingdom. Part of the fun of the adventure was that they needed to escape the city while they guards were looking for them and the King and wanted him and them dead.
In order to allow this adventure to happen, the author had to write a Anti-Magic Field around the King just to make sure the PCs couldn't use a single spell solution to what could be a fun role playing challenge. If it wasn't there, then the PCs could have simply cast a teleport spell and leave without any difficulty. Or they could have simply magically healed the King and they wouldn't need to run.
The adventure was much more fun(IMHO) when the PCs had to find material to disguise themselves and the king, had to come up with an explanation for the guards at the gate as to why they were dragging an unconscious guy around with them, and then had to survive the ambush on the road by enemies of the King.
I think I start to see the main difference between our style and yours.
I am used to play campaigns and sequel games, in which an event (or one big portion of a campaign) is short-cut by some unpredictable measure is not a problem at all. The PCs skipped the entire city-adventure part of the big story? What's wrong is it? The story goes on as long as PCs are living (or at least some PCs are living). The unpredictability and freedom of choice, are something welcomed.
But maybe that is not true when you are playing a one-shot game or something like living Greyhawk/FR games which basically have trouble if "that day's main-part" is skipped unpredictably.
It doesn't have to be prepared by the DM. I just hate magical solutions to problems because they are never creative. They should be the last resort rather than the first solution to a problem.
If I put a locked door in front of the PCs, I don't care if I hadn't considered them climbing to the second floor of a building and sneaking through the window, I'll allow it....If they can succeed in a couple of rolls to do so. At least it required a slightly inobvious solution to the problem. On the other hand "I cast a Knock spell" is about the most obvious solution to the problem there is. It requires no more effort than looking at your character sheet to see if you have that spell.
When magic IS used it should be special. It should be because you did something special to get that magic. Simply looking through a list of 1000 items for the one that solves your problem and saying "I craft that one" or "I buy that one" isn't special."
I tend to agree with you that there are something PCs can't do in 4e. Magics in 3.5e or before were too all-mighty.
But, for me, magic and magic items are part of each fantasy game's "world law" or "physics". Which players can use as the base tool to think of approaches or solutions to challenges and situations. It is basically no different from non-magical measures such as ladder. And no different from blasters and space ship in a space opera game. The world of D&D is sword and sorcery. As sword is not that special, so as sorcery. Magic is part of the D&D world isn't it?
And, do you really think using ladder and going up to the 2nd floor is more "creative" than casting a knock, or using other magical ways to solve a "locked door" problem?
(By the way, this time no rule regarding Knock is changed. It is ritual and not magic item)
Anyway, what I am afraid of is that the large removal of makable magic items will largely reduce the ways for PCs to "re-prepare for rematch" within the rule. As you have pointed out, in 4e, PCs' capabilities are more strictly defined by rules, magic or not, comparing to the older editions. And encounters in the published adventures are more "fixed" and "static" comparing to those of pre-4e modules. So, when PCs fight a combat encounter once, and found that is difficult for them to win (or win reasonably), players tend to feel helpless.
It may not be needed in one-shot game, especially those with physical time limit (like those played at CONs) in which if PCs lose, they lose. But may harm much the playing experience of casual campaign or sequel games played in someone's house or in a gaming club, which re-challenges are welcomed.