I touched on various aspects that would make it a lot better, considering the scope of what they want to make. Drop an entire large zone of leveling(snow zone for example, the one at 25ish). That time could have been used to add one more dungeon or adventure, if not more(not sure what takes longer, I would assume the zone with all the quests takes as long as 2 dungeons but I don't know). Do a quest pass on every hubs/zones in the game. Cut 20-25% of the quests, specifically collecting quests. Also adjust numbers on quests, shit that takes 15-20 of something shouldn't be there, make it 12 max. Adjust overall xp rates to compensate. Adjust kill xp to be higher in relative value to quest xp than it is, not like super high but enough to make grinding at least remotely viable(but still less efficient). Reduce TTK by 20-30%. Buff dungeon boss xp by a lot and/or give repeatable quest xp for completing dungeons. Dungeons should be worth more in xp/time assuming an efficient group than doing quests.
All these changes would simply make the leveling faster, while still retaining the quest theme park system. Nothing is really lost, you're only removing the boring filler quests anyway, and you get more group content by not wasting as much time(obviously now it's too late for that part, the time is already wasted). If your game focus is endgame, then leveling should facilitate getting to endgame, not delay it as much as possible. And don't give me the "you get to learn your class". You don't learn shit when you're soloing quests. Use dev time making group content instead of solo content, because that's what actually teaches people how to play their class for endgame.
And no it's not about removing leveling, even though that's a perfectly valid idea. The current way mmos questing is designed, it's like they design a zone that has say about 50quests worth of content, then they make 100quests in that zone. Make less quests, make the quests more rewarding, make it simpler. If you really want to have people collect bunch of iron scraps in the middle of their quests, make shared objectives: Quests requires you to kill 10mobs, collect 12scraps or a combination, progress is % based(like wildstar is) and both objectives complete a certain %. If you want to only kill shit you only kill shit, if you want to collect you collect. You don't need 2 quests for that, you don't need to force people to do both, it's up to them, result is the same anyway.
You also don't need to make sure as much time as possible is wasted doing menial tasks instead of the fun part of your game. Granted questing is fun to an extent, if done properly. When it's repetitive quests with basic objectives and no backstory/characters, who the fuck cares. It's like korean questing. There's a few fun quests in Wildstar too, they're just drowned in the amount of mediocre ones. If there were less mediocre ones, the good quests would shine more. You still need mediocre quests cause they're easy to make and easy to play, but they shouldn't be most of your leveling.