Warlock changes from the 16.04 patch discussion.

https://www.warmane.com/changelog?expansion=2

Some big changes right there:

-Soul link fixes, removal of minor annyoing bug and exploit fix.
- Demo fixes for arena, certainly a buff but who even plays it?
- Healthstone and devour magic are now able to crit, nice buff, mostly for pvp but will find minor uses for pve. (If only ppl used those candies...)
- Shadow cleave coefficient corrected, big nerf to the skill altough it was hitting a bit hard (20k crits anyone?)
- Enslave demon fix, pretty much never used in both pve and pvp, mostly a nerf to those few locks who used it while leveling/soloing
- Consume shadows fix, super situational buff that will sometimes come in handy in pvp and while leveling.
- Inferno spell power coefficient fix - might be big for demolock - summon inferno for the cleaves and after its over fel domination for your normal pet to continue dpsing, time to complete quest for the skill.
- Demonic pact changes - now the juicy part. Progressive scaling fixed, minor nerf to personal dps, a big bigger hit to raid utility (which is still irreplaceable). Its apllying to pets once again - HUGE, Im certainly logging my lock for the raid tonight to see if imp demo is back.

Demonic pact changes should end up being a buff, same for inferno if its dmg is on the proper level now. Shadow cleave is gonna hurt dps a bit but overall the changes are looking good.

The change log was just a compilation of bug fixes that went through over the course of the past months. Most of the changes you listed have already been in effect for a long time.

None of the fixes are very significant for PVE.

You wouldn't use the Infernal as Demo because it doesn't proc Demonic Pact and doesn't provide you Demonic Knowledge. Resummoning the Felguard also causes it to come back buffless. The spell coefficient fix was to the upfront damage the ability causes when you summon the Infernal, not to the Infernal itself.

Imp shouldn't be preferable over the Felguard unless something broke again. Pets have been getting the buff again for a few months now.

Hah, really shows I should play my lock more. Bummer that imp demo isnt coming back with the way it was last year, focus on fire spells rewarded skilled locks finding the decimation procs.