I don't think this is gonna end up being the final way Wiis are hacked, but I think this shows that big N didn't do anything to fix the security holes in the GC portion of the Wii, which is very promising, using the GC compatability as a backdoor to run all sorts of homebrew stuff.
I see this as a taste of things to come. I am pretty sure they will figure out how to use the Wii SD slot instead of needing a GC memory card adaptor, and newer versions of the software needed will come out that take advantage of additional Wii functionality.
good ol hackers. I love those guys.