Either way, tweaking is needed so I don't see the point of staying on CentOS 4. The kernel needs to be recompiled for XFS support and that means a recompile for every errata kernel release. ext3 + dir_index support is still too heavy although I don't relish a crash on XFS either.
The kernel in the centosplus repo has XFS, NTFS, ReiserFS, JFS support ... the tools for XFS, JFS, ReiserFS are also in the centosplus repo. These will be maintained.
I guess that is good news for my team to hear.