Reread your 3.5 PHB. You may not open a lock without a tool. -2 is for an improvised tool, not no tool at all. You must use a tool to use the open lock skill in 3.5.
You said lockpick. Obviously, you need a "simple tool." It's not like you are going to pick a lock with the
power of your mind. Fortunately, failing the availability of of some kind of sharp, pointy metal object on your person, you can always fall back on battering down the door.
Ahh, so, I can play a diplomatic fighter, so long as I'm willing to wait four or five levels and burn resources into it. The fact that I can't out of the gate can be safely ignored.
That is not what I said. Distorting someone's viewpoint, then attacking the caricature of that viewpoint, is known as the strawman fallacy.
In fact, Regdar, the 1st level fighter, is not only an example of a 1st level diplomatic fighter, but the example of a 1st level fighter. According to one version of him, he has Cha 13, 2 ranks of Diplomacy, and the Negotiator feat, giving him a bonus of +5. That gives him even odds to turn an Unfriendly NPC to an Indifferent one, and he has a 1 in 4 shot at turning a Hostile NPC into an Unfriendly one. At DC 15, he has even odds of turning a given Indifferent NPC into a Friendly one, which is pretty good diplomacy.
Yup, and look at those published settings. Several hundred PAGES of text on how to change these assumptions.
I think you're going to have to provide examples. I'm pretty sure I can do it in much fewer ("Give out less wealth and let the PCs level slower" being the most obvious).
4e, I can change from standard wealth to low magic in one sentence. In 3e, it requires me to rejigger nearly every aspect of the game. "Not all that complicated" is a bit of an understatement.
The authors of the Pathfinder RPG seem to think they can get away with about one paragraph.
Non-sequitor. In all games, the mechanics place limits on the narrative.
You're claiming all limits are equivalent. That's the non sequitur.