Roland of Gilead is about to make South Underrail his bitch. Also, +1 to that Throwing Knives rework. 20% damage nerf seems kinda overdone, but at least it doesn't affect poisons which as demonstrated by sheepherder, the MVP of Throwing Knives build.
Anyway
I didn't see anybody telling you about this, but disable
Auto Saves on Transitions or whatever it's called on the Settings. Really helped a lot with the downtime.
Also, re: Cooldowns
I think cooldowns on special abilities from feats and the more advanced psi abilities are justified. But cooldowns on items and consumables such as grenades definitely felt off. I'd propose replacing cooldowns on grenades with much, much higher AP cost instead, to simulate the player character taking 'nades out of pockets/belts, pulling the pin, counting to 3 or whatever, then throwing it. Following that, with feats like Grenadier and Spec Ops, replace the CDR bonus with AP reduction instead.
For consumables like meds and drugs, maybe apply a semi-debuffs that decrease their effectivity while on-duration? Or hell, maybe even apply a debuff or hell, even some form of addiction and withdrawal on overdose. And then you can remake the Fast Metabolism feat and make it so the debuff last shorter and/or less severe, you're also immune to addiction/takes longer to get there, but in return drugs buffs last shorter as well. Doing it this way you can even expand the usage of Psi-booster where overdose/overusage results in that thing about.... brain-exploding? I forgot. They talked about it in-game. And what a shame it's not a real thing/mechanic, which leads to psi being OP in the first place.
Last, but not least, I'd say the whole cooldown mechanics could be avoided entirely with clever assigning of AP costs-availability, some form of saturation debuff/addiction+withdrawal when using meds and drugs consecutively withing shorter period of time, etc etc. But this, obviously requires reworking of the whole game from the ground up. I hope Styg and co would reconsider cooldown mechanics when they finally move on from Underrail.