WoW Classic Senior Game Producer, Josh Greenfield, has stated that with the release of Season of Discovery Phase 4, there will be two new Vendors that will sell Skill Books that previously dropped in mid-level Dungeons. This change will be implemented to make these lower-level Books easier to obtain on high-level characters and alts.
AggrendWoW
Yeah, this should be in patch notes sometime in the next few days but Milton Sheaf (A) and Zor Lonetree (H) will sell (most) of the rune ability skills that got converted to books and all of the spell books from mid level dungeons (longer blessings, aspect of the viper, druid rez, etc) so you don't feel like you have to grind dungeons in the middle levels on alts to grab that stuff.
For now that's all there is, but we might add more to that later. Some of the brand new spellbooks come from other locations (Avenging Wrath and Valor of Azeroth are two that come to mind that you'll need to go find).
As for rune catchup, we want to do something there but we weren't able to make it work for the launch of 1.15.3. It's not as easy as just putting those runes on a vendor and calling it a day. There's a lot of connective tissue with some of those runes and some important content so its a bit of work to figure out a way to do that cleanly and we just ran out of time for it for phase 4. We do want to do something here though and once we have Phase 4 out the door we'd like to figure out some way to make the rune acquisitions that are a bit more involved a bit easier for alts at the very least, but we don't have any super firm plans yet other than «we'd like to address it at some point fairly soon»… whether that's phase 5 or some other point before then.
In addition to this quality-of-life improvement, Josh Greenfield also teases that after the release of Phase 4, the team will begin working on easier ways for players to earn or purchase Runes from previous Phases. While the acquisition methods are not fully developed, the team
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