Here's a hypothetical: what if used games were abolished, but it meant that publishers felt comfortable decreasing the price of games as time went on? I feel like that would be a worthy trade-off if publishers can be trusted to keep their end of the bargain, but that's a big if.
The TL;DR of this whole argument: we need the economics of Steam on consoles–the money goes directly to publishers and developers, without a middleman to muddy up the waters with diminished disc prices and an excuse to charge for online passes. We certainly don't need to take whatever publishers give us, but we should give the industry an opportunity to present a fair value proposition in which we give them money for the games we want to play. "
The fact that you got the game secondhand is completely skewing your sense of value here. You got one of the best games of this console cycle for $15 bucks. Even if you buy all of the DLC, you're still paying less than retail price for the complete experience. If you value the complete experience, why are you entitled to get it without sending some of the money towards the publisher and developer?
The DLC missions are long and clearly took a fair amount of production resources to develop–while I'm not a fan of being nickeled and dimed (ahem, day one DLC ME3), I made an informed decision as a consumer that the ME2 DLC was worth the cash, so I picked it up. Do it or don't, but don't whine about how things cost money and that annoys you. "

As more games move towards service-based revenue models, we gamers are going to have to do more than complain when DLC seems overpriced. We need to judge the total value proposition of each big release and decide if what they're offering is worth the cash–we can't just buy the next big thing and then pour our rage on to the Internet, because then the Next Big Thing 2 will just come the following year in all the same annoying trappings.
We have to vote with our dollars, not with forum complaints. We can't simply say that online passes are shit–we need to suggest a different model that we'd be more inclined to put our money into. Don't buy DLC season passes without an announcment explaining EXACTLY what you will eventually be getting ("four new pieces of DLC" is not even close to good enough).&nbs"