But you aren’t referring to old canon. You’re calling it ‘Warcraft canon’, and that is not Warcraft canon. Warcraft canon is whatever the latest canon the series decides upon based on its creator; and that is World of Warcraft.
You are specifically talking about WC3 RTS canon, but you are not specifying it that way in conversation. And it makes it more muddy considering you are sourcing from various novels around the time, but decidedly put an arbitrary cork on those that you don’t deem canon.
In conversation, there doesn’t seem to be any common ground or generally-accepted definition of Warcraft 3 canon (outside RTS, such as novels and books). Kinda like what you bring up here with Star Wars EU; at least we have a designation for it; the Extended Universe. Warcraft does not have that because it is one canon - and the latest iteration comes from Chronicles and WoW. There is no separation of WoW novel canon and WC3 novel canon, considering you’re dismissing books from 2006 but you openly admit that the transition to WoW lore wasn’t definite until 2010. So what of all the material within those 4 years? Who decides what is more canon and less canon? How are people to discuss things moderately without any basis of what is considered canon and non-canon?
Warcraft 3 RTS lore would have to be specific to the game itself, and if we abide by those standards then there is literally no explanation and backstory to talk about regarding Night Elf origins or whereabouts of Black Dragons etc. All that is doing is perpetuating an era of blissful ignorance, with arbitrary boundaries that are neither consistent nor reliable.
The most egregious example out of this is if we ever include the Warcraft RPG books (which is based on WC3 lore, pre-WoW), which were technically not rendered non-canon until many years later. They would be technically canon within the timeframe you set, but who gets to decide whether it’s relevant or not? Is it as non-canon as the Magazine, so Ancients like Malorne and Ursoc/Ursol remain never to exist? Because the first mentions of these Ancients were in the RPG books, and they have become a significant part of Druid and Cenarian lore. Yet without acknowledging WoW in the picture, then none of this becomes canon because the other sources where this is mentioned, like the post-2004 Novels and the RPG books, are considered by you to be non-canon.