Achievements are being done to death, though.
I understand the sentiment. But step back and ask yourself -
why are they being done to death? Because players enjoy them. Players want them.
Yes, they're just operant conditioning, as you put it - but that should make it almost a no-brainer to implement them. They're cheap and easy to do; players enjoy them; players will push to get them all and be able to yell "FIRST!" or "MOST!" or "FINALLY!" when they get there. They add another element (pardon the pun) to the never-ending grinding that we face in the game.
And, because of that operant conditioning, new ones can be rolled out fairly often - every week? every month? - without a ton of extra work, and a new batch can be added en masse with a new 1.xx update to reflect the changes and impact of the rollouts. It's also an area where the community can take part, offering suggestions for new achievements, sharing ideas, voting on them, and whatever else they might be able to do.
I like the storyline idea, but I agree that it might be a bit more than Zanz can take on to do it right. Maybe the community could come up with something, save him the work/effort? But, maybe that's the longer-term project/goal and achievements are something that can be added near-term to address a desire a many players.
