Power Zones - % FTP or Peak Power?

Looking at this screenshot from Golden Cheetah got me thinking about power zones. It's in French, but it demonstrates the point better than the English screenshots I could find:

Golden Cheetah, like just about everything/one else, seems to take FTP and assign a % range for each of the zones. I noticed though, that the zones were quite closely aligned to key points in the Peak Power Curve: z3 between 1 and 2 hour peak power, z6 between 1 and 3 minutes.
Since riders are all different, it seems inaccurate to assign their training zones to standard % ranges, rather than to customise them to their specific abilities using the data available.
For example my own, not very wonderful, power curve looks like this:

Adopting peak power based, rather than % of FTP based zones would result in some differences:

Since my target race distance is 180 km, it is not surprising that zones 1 and 2 finish higher than a typical profile. It is perhaps surprising that zone 3 finishes lower. That is probably a personal weakness where I need to devote some time. Zones 4-7 are a bit higher than typical. Arguably, today I am pushing too hard when I'm aiming for z3, but not hard enough in all the other zones.

Another approach would be to assign different % ranges depending on generic rider types. Dr Coggan proposed several generic rider types here:

home.trainingpeaks.com/blog/article/power-profiling
He compares actual power outputs/kg to a standards table and looks at the resulting profile shape, categorising riders as:

• All Rounder
• Sprinter
• Time Triallist/Endurance
• Pursuiter

Perhaps the % ranges should be adjusted for each rider type? Endurance riders might see zone 6 starting a little lower - 110% for example. Zone 7 would similarly be lower. Sprinters might see Zone 3 start a little lower 75 or 80% perhaps.