Any word on new flying mounts or anything like that?
A little, but not a lot. We're not seeing a cornucopia of mounts yet. The ones we have seen are pretty cool, though. As I mentioned yesterday in my post on the Obsidian Sanctum, they're running with the design of Zul'Aman and offering mounts as special rewards from completing 'extra challenges' in raid zones.
The Obsidian Sanctum offers up a Black Drake Mount for completing the special challenge in the 10 man version, and it seems you get a Twilight Drake from the 25 man version, but I haven't seen that personally. Either way, these drakes are pretty hard to get, at least at first. They're not quite giving them out for nothing. Other colors of drake mounts have been datamined, but we haven't seen them drop yet.
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Any news on the legendary drops that could be obtained through 40-man Naxx? Is it still possible to get a corrupted Ashbringer or Atiesh?
As far as we know, you are not able to get either of these in Naxxramas. Ashbringer seems to have been approached differently than originally intended (Tirion Fordring has it) and the Corrupted version is just gone. A dev mentioned at one point that they were undecided on what to do with Atiesh, and so far we've seen no sign of it.
I see that Riding Crops and Carrots are going away. Will my Charm of Swift Flight be disappearing as well?
The change hasn't been pushed through yet, but I would assume that is the case, yes. All items like that are going to stop working after level 70. I doubt the Charm of Swift Flight would be any different, though maybe I'll be proven wrong.
What capital cities outside Dalaran will there be Inscription trainers? I think I remember reading that there will be one in Undercity, but where else?
I believe that every capital city will have an Inscription trainer. It won't be like Jewelcrafting where they hide it away in Burning Crusade only territory. There's a trainer in every capital.
Any murlocs in Northrend?
Yes. Ugh. Yes. Not only Murlocs, but their evolutionary cousins the gorlocs as well.
I haven't heard any news of b eing able to show all questgivers on the minimap since the article about it. Is this something that is now available in Beta, or on the PTR? I took a look at the PTR and either I can't find it or it isn't available yet. Any ideas?
I haven't logged onto the PTR yet personally because of the little issue where Wrath beta testers were blocked from the PTR temporarily, but other people have said that it is indeed there on the PTR. Since I can't confirm it, I'll show you where it is in the Beta. If it's on the PTR, it'll be in the same place.