It sounds like you just didn't enjoy the basic structure of the game, or were putting expectations on it to be something it wasn't (it also sounds like you had a rough few games, which can happen sometimes). I know a number of people who got a little frustrated at first, but worked within the structure of the game and grew to enjoy it quite a bit.
Trader was not and is not a "serious" economic simulation really and wasn't advertised to be; it's a light diVersionary space trading game, more along the lines of LavaMind's Gazillionaire. Pirate attacks are random in nature, meaning they could happen at any time. And yes, you can visit a trade center once per planet visit, since abuses could occur; you could keep potentially keep leaving and returning to the planet trade center (since the values are calculated in semi real-time when you enter the trade center) until the values are what you would like them to be. So that means you have to plan to have pocket money, and carefully consider what you wish to buy once you're there.
The economy isn't total nonsense; certain planets do sell things higher, and other ones sell things lower in a period of time. If you study the planets though in a game, patterns do emerge as far as selling and buying prices in a 20-30 turn period. It does change during a game though. Otherwise, it would be a pretty dry, dull game, shuttling between the "high" planet and the "cheap" planet.
You do make a point about businesses not taking your savings into account. That's something I could add perhaps, in a future Version.
Hope you enjoy the other 3 games more, if you decide to try them. If you have other concerns, feel free to write here, or at my e-mail address in my profile.