The original Master of Orion, in my opinion, is vastly superior to Master of Orion 2. MoO2 had the tremendous disadvantage that, in order for the game to be enjoyable, you pretty much either had to play the Psilons or else build a custom race with the Creative advantage.
Otherwise, you could only research about one-third of the available technology in the game. That made absolutely no sense to me. Sure, you could trade for other techs, but that was annoying, since you'd have to offer the CPU opponents a more valuable tech than the one you were asking for in order to get them to agree to the trade.
I just don't understand why they made it so that researching one piece of technology cut you off from researching anything else in that particular tech group. It was a terrible design decision in my opinion, and the biggest flaw in an otherwise great game.