I see the AL as a way to get existing gamers who are not roleplayers up to speed on what roleplaying actually is. They can see it at their local gamestore and even if they're there for the Pokemon tournament they can see there's this other Organized Play thing going on and hey it's once a week like Pokemon nights and it looks like a fun thing to try.
The APs are for the next level after that. *snip*
I've thought of this before and I don't think that it actually would work well. The overlap between boardgames and RPGs is not actually that great and I don't really think that something like Wrath of Ashardalon (as much as I love it) gives a player a good idea of what a role playing experience is like. I personally like the idea of having more starter sets - along the lines of the "How to Host a Mystery" games. You might need to strip down the rules a bit more, but there's a lot of merit in having a game that maybe doesn't have a lot of replayability BUT is cheap enough that it doesn't matter and is easy enough to pull off the shelf and run on a whim. They could lead into a larger campaign, but they wouldn't have to.
I don't know Wrath of Ashardalon but I did look up a playthrough, and it doesn't seem to be what I'm suggesting at all. It doesn't seem to be using D&D rules for one thing.
What I'm suggesting is that casual gamers could benefit from novel, small-scale game structures building a casual game out of D&D rules. (The Alexandrian has a primer on the subject here:
http://thealexandrian.net/wordpress/15126/roleplaying-games/game-structures--read the first five or six posts, it's quick--and here
http://thealexandrian.net/wordpress...e-structures-part-11-complete-game-structures.)
You've observed that the APs are the next level of a certain kind of game after Lost Mines of Phandelver. Let's call this kind of game "RPG storytelling." You've got a certain quest that you're on and an intended plot structure, and within that plot structure you have a certain group of people you're expected to stick with the whole time and help out so that you can have a collective victory. During play, the DM will typically describe situations to you and then ask, "What do you do?", and then tell you the result. The actions you declare ("What do you do?") are typically expected to be pretty granular, on the order of minutes instead of hours. (E.g. "I go on an adventure, kill every goblin I can find, get lots of treasure and spend it all on candy" is typically going to result in your DM asking you for a different declaration instead of narrating a result.) You're allowed to go off the rails to a certain extent in how you engage with obstacles in your path, but it's part of the social contract that you have to keep chasing the main storyline until it resolves itself, possibly many months later. Notice that nothing in this paragraph relates to D&D rules (how the characters do things). It's strictly about the metagame (how the players do things).
That's one kind of game you can play with D&D rules, but it's not the only one. You could change the game structure by introducing some parallelism (multiple groups of players playing at once, a la
Head of Vecna). You could change the expected scope of action declarations (introduce sections of play where players declare actions with larger scope, like, "I spend a week interviewing all the suspects" vs. "I spend a week researching a new spell to detect blood types"). You could relax the expectation that parties be static--especially in a game with larger scope, there's absolutely nothing wrong with letting the guy who's interviewing suspects have experiences (someone swallows a poison capsule before you can interview them!) independent of the guy who's doing spell research (late one night, a Shadow Demon tries to assassinate you!). There's also nothing wrong with engineering competitive instead of cooperative play (only one person can claim the reward--and the Shadow Demon was sent by another PC!), a la
Mafia. You could drop the "plot" expectation and just have a game of random discovery, like a dungeon crawl except instead of being rewarded by treasure from monsters killed, you're rewarded by memorable and weird experiences like getting to say you once beat Death Himself at the game of Twister. (And Battleship.) You could flip things around and play a game of
Dungeon Keeper where the players have to stock a dungeon and keep it safe against a invading heroes--either pregens run by the DM/GM, or heroes run by other players while the DM acts as a neutral ref. (You could even have no DM at all and just adjudicate rulings by group consensus.)
And you could do a different one of these games every game night, sometimes with a PC that you've played before.
Any one of these games could have a "next level up", e.g. murder mysteries can get more and more sophisticated, but APs are only the "next level up" for a specific kind of game structure. And I think there's a lot of empty design space for creating other types of D&D-oriented games. Just imagine if Wrath of Ashardalon were rewritten to actually use D&D rules and become a form of solo-oriented 5E random play. It's still D&D, but it's now very, very different from an AP, both in the time it takes to play and the experience it creates.
This kind of stuff is on my mind right now because, obviously, I'm trying to create some of these experiences for some friends of mine. Perhaps nothing will ever come of it.