[quote="richb-hanover, post:1, topic:52"]we need to find a way to encourage people not to re-write the flashing instructions, again, and again, and again, and again...
[/quote]My usual answer to such issues is "automation automation automation", fully mimicking Ballmer's "developers developers developers".
You make a template(s) with all the text and commands, then based on conditions and variables you assemble it in the device-specific page.
For example, for a factory update on a tp-link you can make a template with precise instructions, and call it in the device page of all tp-link devices, just changing the device and file names.
They should have the same webinterface after all.
You eventually end up with many template_tp-link_interface_2014-2017, template_tp-link_interface_2017-2020 as they change webinterface once in a while.
Or, for a device that has uboot bootloader you assemble the default "manual tftp flashing with uboot" template with device-specific flash offsets for firmware in the commands, and with brand-specific way of stopping autobooting.
This will probably require to add fields (again) to the toh, if the device can be flashed from factory, bootloader type (I think it's stated already), for flash offsets for flashing, and whatever else is required.
This system will also easily provide decent and updated links to the download binaries without human interaction (yes many OWRT wiki articles still link to random stuff in random places, that's bad).
I heard you prefer playing with templates on the wiki instead of editing, therefore I find some work for you. Happy? 
More seriously, I'm not that good with templates myself and I don't know how to have this happen in practice, so I'd rather have a more expert person do this while I'm mostly editing dumb documentation. Probably tmomas, that seems to be working on templates already from wiki logs.
But I can always learn to use templates, if needed.
[quote]The new page should inspire confidence. [/quote]Keeping all flashing instructions in a device-specific page is much better for this imho, as that's the device's page, people will trust more a device-specific page than a generic one. Because it's the page for their specific device, duh.
As a general rule of thumb, generic guides for everything are dev-only as the "genericness" does not inspire confidence and you can be sure that a generic guide WILL trick noobs as many won't be able to translate the generic instruction to a device-specific one.
I'd say to leverage the machines serving us already to also do the leg work here. Most edits on wikipedia are done by housekeeping bots after all, why can't we?
[quote]The page should offer clear guidance for the most common cases.[/quote]Using a template system should ensure that the common flashing instructions in each device page are all the same even if they are copied in zillions of different pages, as to change the tutorial you need to go and change the template page (that can be locked). Other flashing methods MIGHT have their template too if it makes sense, (like using UART/serial connection, that is required on a non-trivial amount of devices), but the others (JTAG, mind-meld) can be left to manual edits only.
Some specific devices have funky installation procedures, and there only way is manual edit, but as long as the procedure is the same on a class of devices (same brand maybe), you can make a template and use that. Like say Mikrotik_SPIflash_template.