Making "new" guides seems kinda out of place. Not only is there still alot of information from back then available, there came alot of information up for minmaxing available for both leveling and raiding, ontop of various bis gear lists that cover patch progression aswell if necessary. Wether people like or dislike pservers does not make the various information found on their forums less valuable.
Most people who have spent years playing massively multiplayer online games will tell you that there's something special about the first one you played, too—and WoW was the first for many people. You can become so swept up in the uniqueness of your first experience that you overlook many flaws. It's likely many look at WoW Classic with rose-colored glasses, just as many simply forgot which features were added when. And some of today's WoW players may be too young to have even played vanilla WoW as it once was.