I think you exaggerate the importance of edges, but I'm with you on feeling compelled to farm obs/exp pre-30.

The holy grail would be a system that incentivizes the things we want to incentivize but doesn't create any perverse incentives. I feel like the current system creates some perverse incentives.

Specifically with regard to observation/exploration, I would do the following:

1. Take a few veteran staff and have them rank mortals to hero, stopping to hunt along the way, but make no effort whatsoever to accumulate obs/exp. They just do their normal thing. At around the 200 hour mark, check in on each one and see how much obs/exp they have.

2. Note the median observation and median exploration experience from this group.

3. Set these values as the "caps" past which obs/exp no longer generate edge points.

4. Drop all requirements that obs/exp be accumulated by a certain rank.

5. Create logic that "releases" edge points from obs/exp as a character gains ranks. This would prevent someone farming up to the caps at level 10 and generating a ton of points "early".

Some things to note about this system:

1. Veteran players don't have to think about observation/exploration since they can be confident that with a long-lived character they will eventually reach the caps without any special effort. Contrast this with the current system where if I don't get my obs/exp by a certain rank then I permanently lose out on those points.

2. Newbie players still have an incentive to go out and observe/explore since they will probably not reach the caps without being intentional about exploring and observing.

3. There's no incentive to "farm" obs/exp at low ranks in an attempt to generate a ton of edge points "early" since the points from obs/exp only become available as characters rank up.

May not be worth the development time to implement something like this, but from a game design p.o.v., this is how I'd handle the issue of obs/exp and edge points.