Fistycuffs - If throwing fistycuffs at enemies did some type of damage, I could see that being abused. But since it doesnt, does the weight matter? The reason I put 'em on my Runties is for couple reasons: knocking out units that "wake" up behind my main line, when I need to swarm a target with stuns, and lastly it's a great way to train skills on armored units then kill them if they don't go down. (Kind of like in Ironman Impossible nuXCOM where you let rookies take low shots first, but ensure you have explosives or veterans able to put the target down if it survives or trainees miss.)
Player could repeatedly throw objects to train throwing accuracy, especially as there are items in Piratez that utilizes throwing accuracy skills. In X-COM, throwing accuracy did not affect secondary stat growth, but not sure if that was changed in openXCOM, or if it was changed in Piratez. Totally forgot to test that out.
Tac Vest - I haven't bothered using it honestly, I couldn't justify the $$$ for it and unlocked the manufacture waaaay after Smokey Ops Gear & Warrior Armor. I doubt I'll use it even if Laser Res was set to 80%; as again, takes too long to research, costs a hefty price Black Market or rare Personal Armor parts (rare in my playthrough anyway), and Smokey Ops feels like a better upgrade as it spreads armor around, eliminates smoke vulnerability (nothing like throwing out smoke nades and Gals swarming out of the smoke into the blind enemy), only affects stamina, cutting/acid res, and NV 9 (not sure if this truly works on this armor as "Our Abilities" entry states Gals have inherent NV 12?).
To see myself using it, perhaps having it as a downgrade of Guerrilla armor; +accuracies, another Resistance; to make it a viable early-game alternative to smokey ops.
Sidenote: Do personal flashlights (from Our Abilities Bootypedia, default hotkey: L) actually affect the AI in any way? I've replayed the same missions with lights ON or OFF the entire time, on Day and Night missions, and haven't noticed any difference. (E.g., Mission 1a: Day, Lights On. Mission 1b: Day, Lights Off. Mission 2a: Night, Lights On. Mission 2b: Night, Lights Off.)