You are also simply mistaken about the use of many 3e skills and checks. Move Silently, Hide in Shadows, Listen, Spot, and other skill checks have a DC determined by an opposing check, not just a free-wheeling number arbitrarily set by the DM.
Yes. They. Are.
Look. Every time you roll a D20 for a Hide check in 3E you are weighing it against a plethora of different factors such as time of day, who's watching, what the character is wearing because there is no RULE in the book telling you how to define these.
In 1E it's a d100 vs 10 roll, only for a Thief, unless you are under direct observation. Period.
In 3E, there is no such clear strict rule about how this is done.
Other skills like Open locks may not actually be tried by just anyone, but may only be tried by a character trained in the skills.
True, but ANY character can be trained in the skill upon character creation. In 1E, ONLY the Thief can ever do it.
Again, which system is more strict?
Granted, any character can learn those skills, but it's the rogues who typically have the easiest time at it in the various iterations of 3e, 3.5e, PF, and 4e.
Yep, which makes 1E more strict, and 3E more free-form.
Other checks you list are as mistaken as the ones I mention above. Breaking down a simple door has a DC of 13. Bending iron bars - DC 24. Lifting a gate - DC 25. None of those values are any bit more (or less) free-wheeling than those in 1e.
How do you define "simple door" in 3E? Again, this is UP TO THE DM TO DECIDE. In 1E, it's always a 1d6 vs 2 (on str 8-13) regardless of the type of door being opened.
Bending "iron" bars. What about copper bars? What about marshmallow bars? The DM makes this up too for the target DC in 3E. In 1E it's always 1d100 vs 10 (for str 16) regardless of the type of bars.
Do you see how there is so much left up to the DM in 3E? Everything is defined in 1E on what you can and can't do.