I think now that there is relative parity in terms of skill this one night format isn't really feasible. Guys like Royce and Shamrock did well because they could outclass the others with grappling. But now days, the top level guys are so evenly matched that its crazy to expect them to fight multiple times in a night. Imagine if you did an 8 man tournament at 155 lbs. with Khabib, Conor, Tony Ferguson, Cowboy Cerrone, Barboza, Gaethje, Pettis, and Poirier. There would probably be a fatality, just because that's too much damage for any person to handle. I though Pride did well with its middleweight GP (the one that Shogun came out of). Have the first two rounds on a couple months apart, and then have the semi finals and final on the same night, but the fights being fewer rounds. I like the tournament format over the span of several months. Its a nice break from the norm, which is just random match making.
The UFC product and the fighters are light years ahead of what it was back then and despite the hate for Dana White he is a huge part of it's success. If anything I would like to see the UFC bring in some of the elements that made PRIDE so great,such as yellow cards or anything that encourages more action and punishes the fighters continually stalling the action.
Too much money is on the line now to be going out 3 times in one night. I agree with you though, it was the best.