That doesn't seem that esoteric to me: in general the problem is that repr() can result in execution of arbitrary code, and that there's no way to cleanly and reliably terminate arbitrary code. This includes Python code: it's possible to terminate it at an arbitrary point, but that leaves things in an indeterminate state.

I think it's pretty important that you shouldn't add features with unpredictable behaviour into the core of the language, particularly into error handling code.