On Bloodthorn this evening, some guildies and I used Retreating Maneuvers, speed potions, mist form, path of darkness, etc. in various combinations to swim across the channel in two separate locations and reach the center island where (allegedly) the Imperial City resides. "Cool story, bro" to follow, so go ahead and bow out now if you couldn't care less...
If you're still here, you probably have a sense of adventure, too, and maybe you've taken a close look at the broken bridges that span the channel. As some of you no doubt learned the hard way, there is an instant kill spell that hits you for 100,000 points of damage called "Imperial Law" if you go too far on those bridges. But in the water, there are only slaughter fish, and so, clearly, we're meant to try to bypass them -- if not, the water would be instakill also. We found two locations (so far) which worked. I figured the devs put huge rewards on that island for bold explorers to discover. That's what I would do if I were a dev...
The first location we crossed at is here:

As you can see, it's pretty narrow and it only took a few tries testing various combinations of the above spells/potions/skills to be successful. Unfortunately, the devs put an invisible wall just a couple of meters off the beach leaving almost no explorable areas. Additionally, the land is not flat enough to put a camp up. All we could do was snap some screenshots:


The second crossing location showed more promise:

There was no invisible wall blocking our progress and we began to explore... but there is an unnamed invisible instant death kill once you venture too far inland -- death recap doesn't even name it. Very disappointing indeed. We traversed the beach in a few directions, but invariably it got us when we got too far from coast (maybe 3 meters in).

Anyway, we're not giving up hope that somehow there's a way to get inland without hitting a wall or being instakilled. That would be really depressing if bold adventures were discouraged from boldly adventuring.
Peace.
* My compass might look wrong in these screenshots because I pinged/rally pointed the map a few times and bugged it.
ETA: We could not rez each other after being killed by the unnamed instant death.