What add-ons can do has changed over the years and have become much more sophisticated as authors have gained years of experience and savvy. We’re not 100% on a concrete solution to what this means for WoW Classic yet, but one thing we know is that we’re not going to roll all the way back to the 1.12 add-on API. Doing so would open the way for nearly complete automation of combat decision making allowing for “bot” behavior that is counter to the core WoW gameplay experience. This is one thing we know we don’t want. On the other end of the spectrum, the modern API offers some additional functionality for creating social features that could also undermine the authentic classic experience. We’re still figuring out the details and looking for a good middle ground. We’ll be keeping a close eye on feedback from the community and add-on authors on where we should be setting those boundaries.
The quickest way to level up is to travel through the game's zones, completing all the quests you encounter along the way. Completing quests grants you Experience points, which will slowly fill in your experience bar with blue or purple. When the bar fills, you reach the next level. Alternatively, you could choose to run Dungeons or Battlegrounds, which are not covered in this beginner's guide.
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.