Post Main Story Game Play

It really depends on the game, but Fallout 3 for instance used to end with the ending. But with the Broken Steel DLC they extended the ending by another mission(s), and you could play after the ending. It was great to play around after the game was finished to go around doing stuff you didn't have time for, like side quests.

Post game is cool but it feels dead most of the time.

I liked it in Arkham City. It was just a little extra DLC mission, which I got included with the GOTY edition. It didn't really add to the story at all or make you feel like there was more closure or anything (the main story did all of that by itself) but it was an extra half hour of content, so no real complaints.

But I agree with Cervantes, the new game+/hardcore mode thing is way cooler.

It depends a lot on the type of game and even how good it is.
For example, I'd never have bought Dragon's Dogma Dark Arisen if I was stuck in the "story part" of the game, the "after-story" was pretty important there.

I think that you guys have also ignored the fact that arena modes can be easily more important than new game +/postgame for action games because that's how you can elaborate on several ocasions that the player might want to see more of, or see in different twists in an easily accessible way. Like, new game + is almost detrimental to Resident Evil games, but the raid mode in the Revelations series is brilliant.

On principle, I would say that a story is done when it's done and there's no sense in artificially extrapolating it.
Surprisingly, I find this principle doesn't quite translate into practice.

As points of referral, I bring up three cases:

1. Banjo Tooie - After completing the game, there is a sense of permanence in having defeated Gruntilda but still the option to go around fulfilling the collectathon aspects while also getting to party with Bottles and friends.

2. Dragon Quest IV (DS) - I would have told you that this game was perfect after getting brought to tears from the standard game until I played through the final chapter and felt reborn in terms of cultured gaming.

3. Legend of Zelda: Majora's Mask - What's that, you say? No game+ in Majora's Mask? You're right! This is a counter argument and example of how lack of added content can hurt a game. How can I go through a whole game feeling a cumbersome pressure of time constraint only to beat the final boss and feel the added weight of having accomplished nothing? Nearly every event that transpires in the game is temporary and although I consider it a foundational game in my childhood to have experienced, I always longed for a deeper sense of free roaming and purpose in the realm of Termina.

So these are a few case and point examples of what it means to "get my money's worth" out of a game. It's not to say that every game desperately needs more to do once you finish but it's more so demonstration of how a dev team can make their already great game go the extra mile.