I've been enjoying the heroic encounters with dragons that were originally added in the Tyranny of Dragons campaign. Unlike the ones in Icewind Dale and the new Elemental Evil zones, they are not random, but on a steady, visible timer. While this could theoretically make them less interesting, it makes sense from a practical point of view since there is only one dragon per zone, and since these are not endgame areas, nobody has any reason to hang out there for long periods of time just to wait for random encounters to spawn. The dragon fights also require a healthy number of participants to go down smoothly, and the timers help to get everyone in place at the right time.
Since I'm terrible at action combat, I've been dying a lot, but it's no big deal as people are generally pretty helpful and try to revive fallen allies. And even if I get downed for good, the nearest respawn point usually isn't too far away.
The thing that fascinates me is how different the synergies of each dragon zerg are. As a very casual player I have little to no idea of what other classes and specs can do, but at times I've been on the receiving end of some absolutely incredible buffs. There was one encounter where instead of my usual frequent deaths, nothing seemed to be able to move my hitpoints at all, and another where my action points kept refilling so rapidly that I could spam my daily power pretty much non-stop. That was pretty crazy. I just wish I knew which class caused what so that I can follow them around in the future!