Valve never said when they would release Episode 3. Yes, I am looking forward to it, but you can't blame Valve for breaking promises they never made. It's been too long you say? Because Valve never takes a long time to put out their games? Yes, episodic content, at least useing Valves style, was a failure, and quickly, DLC proved to be a superior choice for presenting smaller then full sized gaming content. But they tried something different. I applaud that. In the mean time, there is no drought of video games.
I'm going to go drastically against the grain here, and say that sequels are some of the best games ever made. Strictly speaking, they are usually better then the original. Sequels are good. They give developers a chance to look at the original, and have a better idea of what works, and what doesn't. New IPs and game types are wonderful. They strike new ground, and are great to explore. But quite possibly the biggest thing they give to the world of gaming is the chance to let that new IP evolve, get better over time. Valves sequels are getting better all the time. Maybe Portal jumping loses its freshness the second time around, and maybe the rush of coop zombie shooting just isn't as surprising when you've done it before, but when Valve does a new iteration, sense of freshness aside, the new iteration is, strictly speaking, better. And constantly making better and better games is all I will ask for from a developer. We have played Chess for thousands of years, Half Life or Portal will continue to be worthy of playing unto its 3000th incarnation.
Please, stop complaining about L4D2. Yes, TF2 has better, more regular updates. It would be great if L4D was just as well supported. But L4D1 does have user generated content, a new game mode, a campaign, and some tweaks along the way. Far better then most games out there. Valve was presented with the choice of keeping L4D1 having constant updates, or they can put their energy into L4D2, where they have improved everything, and make a game that is the best they can make. The fact that they make the best game they can make is the reason why it's worth buying from them. And after feedback from fans, they have started treating L4D2 to the constant update treatment. There's a new game mode every week, and they have made a new campaign and are looking into tweaking some very fundamental things. They have gotten better.
Yes, it will be great when Valve releases the class updates on 360. Now, tell me that the Orange Box wasn't still a fantastic deal on console, and I will call you a liar. Sure they are better at developing for the PC, and they don't really develop for the PS3. They aren't doing this because they're jonesing for less money, or to piss you off. There doing it because it lets them focus on making a better game. It's not perfect, but what is?
There is no problem with Valve that can't be solved by simply remembering that other developers sell games as well. Everything Valve has done is good, and getting better with time. You can just decide if this better game is something you want. If you don't, fine. If you do, Valve will keep impressing you more and more.