The human player can abuse much much more features than just tech trading. It can abuse war, it can abuse surprise DoWs because the computer cannot rely on your attitude towards itself, it can abuse a lot of things. That's why the AI gets bonuses with difficulty levels.
So my advice is: play with the system you're offered, and if you think it's too easy, up the difficulty =)
I must say that there are two exceptions, though:
- the broken, buggy, exploitable stuff. I've read that before a certain patch, you could actually lightbulb an infinite number of techs out of a Great Person. That should obviously not be used, because it was not intended.
- stuff that you think will likely be changed in an upcoming patch, e.g. the Apostolic Palace's victory condition ^^
Otherwise, play to your strengths. That's why the AI gets bonuses.