Hi Todd,
The answer to these kind of questions can be very relative. It all depends on what features are invoked currently on this pix being on 6.2.2. There might be some of those features that could have some issues on the 6.1.4.
If things are working fine on 6.2.2, why bother dowgrading? But in any case, the release-notes would be your best friend. Go through these both release notes, see which feature(s) you are using and if there are any red flags for these on the 6.1.4.
From my experience, 6.2.2 has many bug fixes and new featues added.
Release notes for 6.1.4
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_sw/v_61/relnotes/pixrn614.htm
Release-notes for 6.2.2
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_sw/v_61/relnotes/pixrn614.htm
Hope this helps,
Yatin