In-game mail between guildmates now is instant, but in the past, it had a 1-hour delay, just like mail between strangers. The change to instant mail made things more convenient, but removed the social interaction of having to meet up with someone to make a transaction if you wanted something sooner. So we’ve reintroduced that delay for that reason. Other conveniences such as auto-completion of names or quickly clearing a mailbox have been left in. This seemed an easy enough call given that someone could create an add-on to do the very same thing, and we felt those sorts of conveniences didn’t impact the fundamental “classic” experience.
Once we had our starting point, we began taking stock of what we had in the source code and what we could make available, which included restoring the original development database from archival backups. After stitching various key pieces together, we had a locally rebuilt version of Patch 1.12 running internally. The team could create characters and do basic questing and leveling—and dying, which we did many times. For testing purposes. Obviously.
For another example of lighting, we looked at Elwynn Forest. We had a period in Warcraft’s history where we changed all the lighting equations and as a result, our environment artists had to take a pass over all of the zones to improve the lighting and take advantage of the new equations. To recreate the original experience, we had to rewind those changes. The first thing we did was restore the old lighting data. This brought us much closer to the original lighting—and with a few more changes to the distance formula, fog formulas, and some changes to shadows, we were able to bring things even closer to the original lighting.