FWIW, I agree, but I don't have a lot of choice about this legacy feature.
While the examples shown speak freely of 16-byte aligned vectors which is the most common case where this issue comes up, it is also very frequently used for cache-aligned structures, and occasionally larger.
This feature was shipped in GCC 4.0.2 and 4.1.1 as part of the publicly available Sony-Toshiba-IBM Cell SDK. GCC 4.0.2, 4.1.1, and 4.3 in the Sony Computer Entertainment PS3 SDK also implement this feature. SN Systems SNC Compiler for PS3 has this feature to match GCC, and SNC for the forthcoming PlayStation Vita platform also carries this feature. I would not be surprised if other developer tools such as those from CodePlay, Metrowerks, Coverity, Klocwork, etc. have implemented this feature for parity as well -- I can't say offhand.
We're committed to cleaning this up and supporting it as necessary.