They did sort of expand exploration in MoP... kind of. It's not actually all that special, though.
EQNext exploration does sound fun. I absolutely love the idea of a world that's changing. Rivers moving, bridges breaking, trails getting overgrown, etc. Sounds like so much fun.
Wildstar is also taking a critical look at exploration with their path system. Essentially, when you create a character, you choose a path for them - soldier, scientist, explorer, and... builder? Or something. This creates custom content for you as you level, and you get a very different experience from someone who is on a different path.
Scientists are for people like me, who want to know the lore and story behind everything and like exploring and story stuff. I get to analyze artifacts and things for data, explore ruins for scientific advancements, etc.
Explorer (or whatever it is called), is more for the parkour-loving players. The ones who want to go out and explore the world, but less about "I want to go see Uther's statue" and more in the "I'm going to get to the airport" style. Their path might lead them to otherwise unaccessible tunnel systems to explore, they get climbing puzzles, PVP races and PVE time trials, etc. They're the ones who are going to see a rock pillar system and get custom content to drive them to the top of it.
The builders actually build things like bases and quest hubs out in the world, which creates unique content for them and other people. They aren't limited to these, either, but it seems like they can actually create towns. So over time, zones will probably fall in and out of favor, as the builder players move around. And what they can set up seems dependent on what kind of infrastructure other builders help them set up, and probably changes depending on what services they want to offer.
Soldiers are for the people who just want to kill ****. They get boss battle content, quests that involve enemy hordes, and things like that.
I'm excited to try it, and hope it works out. The premise of letting people build quest hubs and the path system makes it sound like they're using a lot of custom content generation systems. Like I find myself in a set of ruins, and what I research there sends me to a new set of ruins. But en-route I run into an enemy-constructed base and that changes my quest path towards researching opposing-faction tech stuff. Etc.
I'm trying not to hype it too much in my mind, but it's hard. They make a really great trailer.