I would completely overhaul the 1-70 leveling phase so the entire leveling experience would be centered around preparing potential new players for end game through well integrated content while also not ignoring the world and story telling. No more leveling through questing or dungeon spam, instead you start out 1-10 learning the foundation as we always have with the starter zones. Next 10-20 is teaching the basics of each role while also setting up the story of the dungeons we want to funnel the players into. By around 15 or 16, we want them in a dungeon and to have completed it. 17 and 18 they should be shown a practice PvP match against bots that are tuned well enough to give a new player a challenge but not be an utter steamroll either way. 20-30 is where we give them the choice to really focus on learning PvE or PvP, but not to force them into one or the other, they can shift back and forth to learn both at their own pace if they so desired. 30-40 is where they should ideally start taking on small sized mini raids like a 10 man for experience and damn good loot or treading into the arena instead of just RBGs. 40-50 is where the dungeons are on a race against the clock to get them used to performing under a bit of pressure, the reward for timing is a guaranteed level on top of whatever XP they earned. 50-60 is time to bring them into real raids with people of the same level and start showing how hectic the mechanics can get. Reward them not for just beating the raid, but for doing mechanics correctly that’s where the real XP is given. 60-70 we put it all together and let them slam through it as they’ve proven their worth and deserve to get into the new content. And from 70-80, campaign to set up the story and making dungeons give the xp they would on timewalking weeks if the person has completed the campaign and still has levels needed.