if that's your "good legal reason" to avoid the GPL, then it's just as much a "good legal reason" not to open source your work at all: if the GPL is not enforceable, that would mean you have used a non-copyleft license, which according to you is the thing you want to avoid for good legal reasons.
you said "avoid gpl". reason? "unenforceable". eliminating gpl from consideration, thus you advocate non-copyleft licenses instead.
with me so far?
but gpl's "unenforceability" could only mean it turns into a non-copyleft license, one which you say one should not use, so if one shouldn't use gpl because in reality it is a non-copyleft license, then you must be against non-copyleft licenses.
just to state it again for clarity: "don't use gpl because copyleft is unenforceable so gpl is just MIT underneath, and I repeat, don't use it" is a recommendation not to use MIT license.
Note that I don't agree that GPL and MIT are equivalent, or that GPL becomes a non-copyleft open source license if not enforceable. IANAL but it might revert to the regular copyright law for wherever you publish software, not an open source license.
(also, it is enforceable and has been enforced, but that's a separate topic.)