I preface this by saying, I am not trying to be mean.
 
Dupes are a part of the game, learn to deal with them. And I mean that not in a condescending way, but as constructively as I can express it.
You obviously have just started playing AGoT, and that is awesome!
No doubt your learning curve will be steeper than some who have been playing for years, but after a few weeks you will figure out how to deal with dupes.
The game is not unbalanced by them, you'll just have to take our word for it (having played the game since it started as a CCG nearly a decade ago).
If you can still honestly say you think dupes unbalance the game after you have played for six months, I will shake your hand and agree to disagree.

And furthermore, one of the most valuable skills you can have in this game is the metaknowledge to try and suss out exactly what the other player's game is.
For example, I ran a CI deck with a single copy each of Minelayer and Sensei (since I tend to stack up ice on centrals, both of those seemed worth trying). In one game against a Shaper, I put the Minelayer on HQ, and when he ran it I only had the Sensei in hand, so out it went. He ran it again, saw the Sensei, and jacked out, and didn't run again. I thought I had HQ taken care of for the time being, until he had the cards in hand to install Gordian Blade, Account Siphon me and then Same Old Account Siphon me, all in one turn. I didn't see it coming, which some might say is a rookie mistake, particularly since Gordian Blade is a potent breaker against a server guarded by two Code Gates. But nowadays I've very wary and counting influence to see whether that Account Siphon is one of their splashes.
Another example is the one I used: TWIY* is generally a fast deck that doesn't have the luxury of having different paths to victory between the deck size and Influence restriction, so when I sit down and I see that ID, I'm generally trying to figure out as early as I can exactly what kind of game they're running. If you just hand me the information that you've spent 12 influence on 3 Scorched Earth versus 3 Biotic Labor, you are giving me exactly what I need to attack your deck in a certain way.
Even just a small giveaway is potentially game-changing. Shinobi has shown up in a couple of NBN decks. Some Weyland decks are running Edge of World. If I'm walking around having finished my matches and I see an RP deck with an Encryption Protocol in his hand, I can make educated guesses. If I see a Snowball or a Morningstar in a Kit deck, that's very valuable.
The hidden information and bluffing in this game is so important that I'm really at a loss as to how someone could be so naive as to cut their own throat in such a way, even if it weren't against the letter and spirit of the rules
 

I disagree. The game of netrunner is a game of hidden information. A Weyland deck that doesn't run scorches (but pretends it does) and uses the deck slots for something else is a very powerful deck. But it can also rely on the fact that a runner will slow down in order to find the plascretes. I actually think that's a valid strategy to bluff having scorches in your deck. However if a runner knows for certain that you don't have scorches then they are at an unfair advantage. And the same thing applies for the runner. Knowing what breakers and tricks the runner has can give the corp a huge advantage and actually change the way they would play vs a deck they knew nothing about. So I highly disagree that a deck is supposed to win even if your opponent knows exactly what's in it. vs what's possible to be in it. 

allow me to be more blunt: ABSOLUTELY NOT on either of these. Scouting of deck contents and deck lists is expressly forbidden by the tournament rules. You may not share or ask for deck details until the tournament is over.
The reason for this is simple: anyone who says "there's nothing to be gained in surprising an opponent" hasn't been playing this game for very long. Hidden knowledge and unexpected card choices are absolutely at the center of this game. If you disclose to your opponent that your Weyland deck doesn't actually have Scorched Earth in it, or that your The World Is Yours deck spent all its influence on biotic labors, you are giving up a tremendous advantage.

Thanks guys for the responses. I think for now I'll work on picking up the data packs and once I'm caught up, if I'm looking to play more than casual games, I'll grab another core set.