Personally, I think it's more symptomatic of the problems of filesystem-oriented journalists. See the comment quoted by sciurus.
(Irrelevant note: I really don't recommend reversing all the arrows in a Unix kernel. But I like your username anyway.)
There is a bug in ext4, https://lkml.org/lkml/2012/10/25/521
Note that this is dated after the "Wed, 24 Oct 2012 17:31:29 -0400" post and talks about changing code related to a truncated journal.
My post does not say anything about the likelihood of the dataloss due to such bugs, I mention what happens in every design in a WAL journaling system.
Talking about the impact of a particular ext bug is up to the people who post on the LKML. To be honest, I don't really care how severe the bug is, I care about why there are bugs and journal truncation is a source of them.