by andreww
If the knowledge tiles are more powerful, that only gives an advantage to the player who a) realizes that, and b) puts the effort into placing ships so they go first and can grab those tiles.
Remember that shipped tiles are only worth 2 points in a two players game, but 3 or 4 points in a three or four player game. Certainly you're more likely to ship all four colors of goods in a two player game compared to a four player game, but I shipped all six colors in a four player game last night.
Also, half the knowledge tiles don't even appear on the board in a two player game.
There's no question that the game feels different when it's played by two versus four players, but I don't think any of those tiles actually break the game.
If you reduce the number of goods tiles you might also need to bump the per-tile VPs back up to four, otherwise the warehouse building becomes less valuable, which also weakens the four-points-per-warehouse knowledge tile, etc. If the goods are worth four points I think you could halve the number of goods without breaking the game, I think.
Still, having played a lot of two player games, I don't think there's a problem.