The trade rules are very much dependent on the campaign type, aren't they? For example, I think people should be able to get wildly rich and use as many mods on the CT tables as possible. Other folks think money should be more restricted so they don't.
I'm very much a "figure out the rules to suit the game" sort.
The trade rules
need to do 3 things -
1) assuming a reliable and pretty typical situation, allow for freighters to turn a profit after paying the mortgage
2) provide for enough difference in value to support goods moving in the first place.
3) provide enough information that one can have some clue as to what's there when you get raided or otherwise wind up paying for the lost cargo.
CT Bk2 did 1 and 2 well; 3 was more iffy.
CT Bk 7 Merchant Prince broke verisimilitude for many by making all cargos the same base price. It handled 1 and 2 reasonably well, but only for ships over a few 1000 Td, but not much over 5000... (Why? because they can't fill up. And below 1000Td, the bridge tonnage eats your profit margin)
Note that MT, TNE, and T4 produced slight variations to MP...
It's nice if a trade system also...
4) has use for multiple characters
5) can easily be used for larger scale situations
6) is fun to interface with.
7) doesn't bog play down with need for long calculations.
8) provides adventure hooks.
MP fails for 4 and 8. Many feel it fails 6 and 7 as well.