Another old school Greyhawk fan here. I think this new map looks great and most of the changes are only to a few place names printed on the map, for obvious reasons. But in most cases these have simply been replaced with alternate names that also come from Gygax, which I think shows appropriate respect for the source while acknowledging that the times they have a'changed.
There are a ton of little details that show that WotC put the work in to respect longtime fans, so I appreciate that. I'm a bit agnostic about adding dungeons to the map, because that can become a bit of an issue depending on how it is to be used. Knowing exactly where they are is great for the DM, but kinda spoils the mystery, not to mention the investigation, if you want to use the map as a forward-facing resource with your players. Which I normally would. So I would have preferred a second, smaller, "DM's eyes only" map inside the DMG as the repository for those locations, rather than the big map itself.
But, I mean, I can deal. The upshot is that we're getting a beautiful new Greyhawk map included in the DMG, and that was on my fantasy checklist for the DMG, so I'm pretty thrilled.
Here's what I believe I originally posted as my wish list for the new DMG back it was announced:
1. Must function more like an actual guide, using plenty of examples to show new players how to play, and offer suggestions for experienced players: CHECK
2. Should include sample, playable adventures: CHECK
3. Should include a sample campaign setting, preferably the OG setting, Greyhawk: MEGA-CHECK.
So I can't complain. I mean, we're getting a new, much improved (IMO) and lavishly illustrated DMG combined with a new Greyhawk setting and a bunch of small adventures, plus a map, for 50 bucks.