I posted this suggestion years ago, also based on what some others stated / mentioned as well.
I null voted for now, that is because I switched from SC to HC from then, and I no longer skill like I once did.
However, if it was balanced to 50% of your rank, and 100% times harder to gain prof points, then maybe.
How would this work out with coding?;
... All your characters have like Rank 2 Fishing (x8 up to x16 characters) total? Rank 16 up to Rank 32 Fishing?
That will not work, thus, you have to work it out by the total Proficiency Points accumulated on each character because gaining a Rank goes up by 1000 per Rank in addition to the Prof Points gained to get there.
Rank 2 Fishing = 2000 prof points multiplied by 8 characters with the same amount of prof points = 16,000 prof points, thus the highest Rank you will achieve is Rank 5 with 500 prof points = 5,500 prof points.