The WWE Championship is the most prestigious championship in WWE. One could argue that the championship that is curently one Raw is the most prestigious. That may hold true onscreen, but it is not quite the case in the grand scheme of things. The World Heavyweight Championship was Raw's world title from it's creation up until 2005 and then again in 2008, so for roughly 4 years it was BOOKED to be the most prestigious title, when in fact it was not. The WWE Championship has been around ever since Buddy Rogers in 1963. It has remained the top prize in the WWE for decades. The list of wrestlers who have held it shows easily that it is the most prestigious belt in the WWE due to the legendary history it has and how long it has remained the top prize in the biggest wrestling organization in the world.
Still disagree? Let's take a look at the other titles. The World Heavyweight Championship has only been around since 2002, folks. It's DESIGN is legendary and historic having paid tribute to federations like the NWA or WCW. Not the belt itself. It was born when Bischoff handed it to Trips. Then you have the Intercontinental Championship, it has been around since 1979 making it the second oldest title. The United States Championship, even if you count the WCW history behind it, is only a couple of years older. WWE has had it since they merged with WCW and it has been around since 1975 in the NWA. The Tag Team Championship's history only includes the set of belts they created in January 2002. The older belts were retired upon being unified at Wrestlemania 25. The same can be said for the Divas Championship, it is the youngest belt, the unification with the Womens Championship ended the history it provided. None of the other belts that are currently active come close to the WWE Championship in prestige or history. It wins hand down, regardless of designs or which belt is currently on Raw.