I’m thinking you can’t be understanding what is involved here because you really didn’t describe any problems.
What abuse? There isn’t a way to abuse this. All the tag does is make the link essentially the same as most javascript links are now. Big deal. There’s no abuse in that.
At the same time, what it accomplishes is to make it harder for non-owners of a webspace to get a credit for creating their own links on someone else’s site. The fact that it doesn’t fix the problem on abandoned blogs is basically irrelevant. It does what it does. It’s just one thing with no downside. Of course some folks will use it just like they use javascript links now, but aside from being able to do something they could do before but now do it with cleaner code, how is that an issue?
If it did lead to the destruction of automated link exchanges because nobody trusted anybody else anymore, that would be worth the Nobel Peace Prize.