I started to post again to clarify that point. But decided not to.
My understanding is that those patches keep existing files from being zapped, but still provides significantly less in the way of guarantees for the data integrity of new files. I simply don't see any room for reliability regressions at default settings, relative to ext3, in the name of performance, period. Old files, new files, whatever. If delayed allocation makes your data less safe and that can't be fixed, then it needs to be turned off by default. People can turn it on to get their benchmark numbers.
One of the major benefits of delayed allocation is supposed to be reduced fragmentation. Well, we're supposed to be getting an online defragger, aren't we? And I thought ext filesystems were already supposed to be doing well enough on fragmentation avoidance that we didn't really have to worry about it anyway.