UFC 146 is unlike anything else in the long history of the UFC. Never before has the promotion considered filling a card with heavyweight fights.
The major reason it's never happened is due to the lack of quality heavyweights in the UFC's biggest weight class in the past. Just a few years ago, the division had a few top contenders and a rash of guys who were as far away from title shots as you can possibly get. It's hard to fill up a pay-per-view card when you have Tim Sylvia, Andrei Arlovski and not much else to speak of.
That's no longer the case. The UFC's heavyweight division has grown by leaps and bounds, and it's now deep enough that a card of this nature could finally be created. The top of the division is more stacked than ever, with guys like Cain Velasquez, Frank Mir, Fabricio Werdum and the suspended Alistair Overeem all close to title contention. Rising young stars such as Travis Browne and Stefan Struve are filling out the middle of the division.
And that's not even counting Daniel Cormier and Josh Barnett, who will make their way to the UFC after each fighting once more in Strikeforce.
Point being, the UFC's heavyweights are ready for a showcase like the one they'll get on Saturday night. Whether or not they'll deliver exciting fights is a different story.