While Safer Seas does need to have a handicap since there isn't any risk of PVP, I think having it be dropped by 70% is a little extreme.
I would recommend instead of limiting gold gained, add a new currency to the game.
I suggest bringing back Silver to the game, have the PVE mode have everything be Silver... basically the same as gold, but it can only be used in the PVE servers.
Or, if you wanted to give a bit of a "reset" to the High Seas: start transitioning the main game currency to Silver. For a few months have all items turned in give both gold and silver, giving people a chance to spend all the gold they have acquired, but any new items added to the game cost silver, and then slowly transition everything to silver. (Or if you want to make it feel 'better' have it be Platinum).
The 30% value does work... though I would also recommend having World Events turned off on the PVE servers... but I personally think the extremely slow progression would turn people off the game instead of just the mode.
