- Blizzard has decided on 1.12 as the baseline version for WoW Classic. As much as we will all regret missing out on the days of 5 minute paladin blessings, 1.12 is a good choice. Far enough in so that a lot of the really wonky stuff got ironed out, but still with the classic feel. I understand that most of the private servers use 1.12 as well, so it is in line with community expectations.
- The team has the 1.12 code and 1.12 data. Important, because it means that team doesn't have to recreate it from old memories.
- The team has a 1.12 build running internally. This means that they have a "source of truth" for the project. No matter what path they go, they can always compare their latest version with the 1.12 build and know that they are faithfully recreating the classic feel.
- Blizzard has decided to go with the modern WoW engine, but use the 1.12 data. This is mostly good, because the modern WoW engine has all the bugfixes and is tuned for today's computers. For example, the 1.12 was 32-bit, if I recall correctly, but modern WoW is 64-bit. The only issue might be if the older data trips the modern anti-cheat measures.
There's also some details on the different formats of data. Old WoW data is apparently "de-normalized" in many ways, probably for peformance. Meanwhile modern WoW uses a more normalized form.
All in all, WoW Classic appears to be pretty far along. I wonder if Blizzard will surprise us with an early 2019 release.