Has anyone developed a campaign that foregoes the objective based races and utilizes a reveal-as-you-go based on LOS dungeon? I want 2e mechanics with 1e style quests. Does it exist on the vault? If not I’ll make it myself.

You can just toss in a bunch of tiles and create a story on your own while playing. Place a notorious Waterfall tile and say that the water space is Meriod's spawning point and also contains sacred Water rune under it.
This way It takes much less time to setup the game.
Encounters will get much more diverse both for heroes and Overlord.
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The downside of this is that the heroes will constantly complain that you are going too hard on them. Also the game looses its competitive part, but to me it is still nice to play.

Here's just a couple of pros/cons with "reveal as you go" that I've seen.

PRO - Having those surprises for the player is super rewarding on both sides of the table. That's a huge draw that makes balancing the cons worth it.

CON - It breaks up the flow during the gameplay session. Even if you tell the OL in the campaign log to set the tiles aside, they still have to pause everything whilst they dig out the pieces. If it's a big reveal that can eat up a bit of time and break momentum. Laying out MOST of the map first, then segmenting it off with barriers and having the OL populate the tiles as they get through each segment does speed it up a lot.

CON - You're giving the players a moving finish line. This is troublesome since the heroes need to know how to pace themselves. It's a little anti-climatic, but giving the players some indication as to how far along they are is more fair.