Just like stealth... I've always felt the vagueness was kind of the point. Because there's no single system that will please everybody, so trying to go deep on any one method is just going to tick off everyone else who didn't get the system they wanted.
Everyone has their own ideas of what they want and they need to get traps, sneaking around, encumbrance, attacking with surprise, tracking, the skill system, etc. to work the way they think it should go. And WotC either chooses one and goes all-in on it, or they just present a barebones foundational system of "Here's the thing, and here's how to mechanically do the thing" and then lets every experienced DM who has their own ideas add on or re-write the system to be the way they prefer it to work. And WotC lets their own work push new DMs forward on the beginning path they've marked off.
Could WotC go more in-depth on teaching DMs how to make more involved traps that turn them almost into encounters themselves, giving all kinds of lists on "Here's how traps work, here's the ways they can be hidden, here's the ways they can be triggered, here's the ways mechanical traps should differ from magical traps, here's all the different skills and/or spells that could be used in these ten different patterns to find/disarm the traps along with the ideas players should be figuring out to even allow those things to be used in the first place"? Of course. But then you'd get that one DM who'll start ranting something like "Once again, MAGIC is now been crammed into another part of D&D and WotC shows their bias towards spellcaster superiority once again! This whole thing is CRAP!" And the same arguments will be made by any number of other DMs for any number of other parts of the system WotC put together.
At some point I just think that we experienced DMs should just accept that baseline D&D is not written
for us. Because we don't NEED it to be. We all have piles upon piles of other books, other systems, magazine articles, websites, rules compendiums so on and so forth that we have collected over our lifetimes that we've used to assemble our perfect method for running our games in the style we prefer. But if we have all of this stuff, then why do we then need WotC to include it in their books too? Just for the ego boost? "Ha! I run D&D the proper way! The way WotC agree with me on!" Seems to me it's no different than the DMs who've been complaining about Spelljammer-- "The new Spelljammer books haven't gone far enough!" Well,
of course not if you have compiled 30 years worth of Spelljammer material already! But if you already own all that stuff, why in the world would you need WotC to reprint it in their new books?
These books are all just tools. And there's nothing wrong with having outgrown your "introductory tool kit" that you got originally for Christmas and you start using the more advanced tools that do the jobs you need done. WotC sells us the manual Phillips Head screwdriver. We don't need them to be the company that sells us the DeWalt 20V MAX Cordless Brushed 2 Tool Compact Drill and Impact Driver Kit With Magnetic Bit Holder too. And least not in their introductory took kit.