Next thing: The actual suggestion. I, too, have stated that I think the proposed suggestion would benefit pirates. Like I have said too many times, though, the problem is when you increase the percentage of gold stolen, and decrease the max amount. That makes the difference between a "minumum" defence and keeping lots of gold (making you lose the max amount) too small. So I think the maximum amount has to be increased too - not decreased.
CJ's "new" proposal, which basically is identical to the old proposal, except "pirates" have to study a technology to get THEIR benefit (a higher percentage stolen) and "merchants" having to study another technology to get THEIR benefit (reduced maximum pludered), will, in practice, produce the same result for a "high level" pirate against a "high level" merchant - except they now both have to spend lots of gold studying first, to GET these benefits. I think that it would be better to introduce this WITHOUT such technologies, but like I have said before, I think the best idea is simply to increase the maximum plunder amount rather than decrease it.
However, I think that if more "action" is desired in the game, there are other places to look than at the plunder formula (although it should be increased a little, I agree with that). I point again to my suggestion "wars and blockades", along with "nation change barriers". This will allow pirates to attack ports for gold and ships, and it also makes naval combat a part of fighting over ports. It also makes it more difficult for one nation to have lots of ports, I think. It makes ports more costly to hold, so it should go along with an increased benefit from holding ports. Perhaps tax BOTH when buying /selling from ports (not only one), a higher tax from NPCs, and a duke bonus to "party" cards. I realize that this is a rather radical suggestion, but I DO believe it would add more action to the game, and make the game more interesting to everyone.