Actually I like the change, finally a reason not to use D rated lightweight (except on those Alliance things...) anywhere.
But the habit of slipping in changes without mentioning them in patch notes is a big, BIG No No FD ! Seriously.
I already used A rated life support on some of my builds. It's not nearly as heavy as something like the distro or bulkheads.
On a Conda, the difference between g5 lightweight A rated and D rated life support is only 2.8 tons which is a jump range diff of about 0.05ly. So I actually brought A rated life support on DG2 and was glad I did.
While I never did go over 7:30 on oxygen I almost did twice, and I was happy to have the peace of mind (yes I know it can be synthesized but not readily in combat) for what was probably a difference of 0 or 1 jumps over the course of hundreds (thousands?).
And sure there's a tiny speed/agility penalty but in some cases I'll pay that.
(In case wondering how I lost canopy on DG2, ATR vs. a garbage combat build is no joke)