As to corruption, you might want to read some nice papers by CERN presented at HEPiX on silent corruption. It happens everywhere, and it can have subtle effects. But as a legendary quote goes, "as far as we know we never had an undetected error" (mainframe IT manager interviewed by Datamation many years ago) is a common position. Thanks to 'ogginfo' you have discovered just how important end-to-end arguments are.
But the main issue is not that, by all accounts 'ext4' is quite reliable (when on a properly setup storage system and properly used by applications).
The big problem with 'ext4' is that its only reason to be is to allow Red Hat customers to upgrade in place existing systems, and what Red Hat wants, Red Hat gets (also because they usually pay for that and the community is very grateful).
Other than that new "typical" systems almost only JFS and XFS make sense (and perhaps in the distant future BTRFS).
In particular JFS should have been the "default" Linux filesystem instead of ext for a long time. Not making JFS the default was probably the single worst strategic decision for Linux (but it can be argued that letting GKH near the kernel was even worse). JFS is still probably (by a significant margin) the best ''all-rounder'' filesystem (XFS beats it in performance only on very parallel large workloads, and it is way more complex, and JFS has two uncommon but amazingly useful special features).
Sure it was very convenient to let people (in particular Red Hat customers) upgrade in place from 'ext' to 'ext2' to 'ext3' to 'ext4' (each in-place upgrade keeping existing files unchanged and usually with terrible performance), but given that when JFS was introduced the Linux base was growing rapidly, new installations could be expected to outnumber old ones very soon, making that point largely moot.
PS: There are other little known good filesystems, like OCFS2 (which is pretty good in non-clustered mode) and NILFS2 (probably going to be very useful on SSDs), but JFS is amazingly still very good. Reiser4 was also very promising (it seems little known that the main developer of BTRFS was also the main developer of Reiser4). As a pet peeve of mine UDF could have been very promising too, as it was quite well suited to RW media like hard disks too (and the Linux implementation almost worked in RW mode on an ordinary partition), and also to SSDs.