Mind that btrfs will remain in RHEL7, but as soon as you go to RHEL8... you could just build your own kernel. Or use the centosplus kernel which will almost surely include it (as they've been including various RH-disabled modules for RHEL6 and 7 already).
> That's bad, Btrfs has really grown on me, especially the ability to mix drives of different sizes in a RAID configuration.
That's nice, but the fact RAID 1 still is implemented with critical defects might help understand RH position.
Or, assuming you get over your partition resizing fetish, just stick with XFS. It's as close to bulletproof as you'll find on Linux.
XFS is just not flexible enough, I don't like to be unable to shrink a partition once created.
It looks like I'll be back to ext4 and various kludges then.