Are the 2-3% reload/cooldown/acc/pen/armor even remotely worth it?
At first glance I'd much rather choose bulletins like the 10% veterancy bonus ones or faster barrage reload etc because those seem to yield much more significant results.
Accuracy for infantry squads is always good, because that increases their damage output. It's also worth to mention that a unit which you are supposed to build several units or use through the whole game, benefits from having bulletins way more than a single or few units which might be use sparely.
Vet bonuses are nice, but when you manage to hit vet 3/5 they stop benefiting you.
Barrage bonuses are only good as long as you can use them on cooldown and that's generally not a good way of using your indirect fire (you'll take some time to find a good target).
With the removal of duplicate bulletins, most of niche bulletins lost value. Which is fine cause some combinations where broken and forced you to "farm RNG bulletins drops" in order to get 3 of them. 33% increase vet gain, triple increase RoF on MGs (this increased suppression and damage), 3x barrage cd (i think you got something like 20s off from Stuka), etc.