Regarding Peace Walker - there's no need for Dan & Drew to play that. I'm on the fence about even bothering to continue with it myself vs just moving on to MGS4.
I don't think you'd say that if you actually finished the game and went onto play Ground Zeroes. Like I've said many times, playing MGSV without playing Peace Walker will be like watching Episode VI of Star Wars without watching episode V. If you want to keep a proper bearing on the story, you have to play it. Or watch it on youtube, whatever, but then you might as well watch MGS4 on youtube without playing it as well.
Drew and Dan don't have to include it in the series, but Drew has to play it before he finally gets to MGSV. Or else he'll be like Brad who was trying to say during one of the GOTY podcasts that he missed playing one game, and now he has no idea what the hell is going on. It's unfortunate that it was made a PSP game, but it's as important as any other of the numbered entries.
I just meant I don't think they should play it for the purposes of the website, not in terms of whether they should play it in general.
That said, I didn't realize there was much story to that game, or that it was important. Based on the few hours I played, I got the impression that the plot was going to be thin (due to the game's structure of taking missions from a menu) and very much a "side story" sort of thing, but I suppose I should know better.
On an unrelated note, when Dan and Drew do start MGS3, I really hope Dan doesn't let Drew sit through the pre-menu opening or let the game go into "attract" mode so that Drew's first exposure to the "Snake Eater" opening is when it's presented in game. It's way more memorable and humorous when encountered as a Bond style late intro and it's unfortunate that they also use it as the pre-menu opening and spoil it.