For me?
- Storm Their Lines!: Stormtrooper +speed +accuracy
- Guards Rifle +sight +whatever else that one did
- Jagdpanzer IV +literally anything except build time
- Shoot for the Stars: Artillery Field Officer +nearby artillery range
- Live and Learn: Riflemen +veterancy
- Pack Howitzer +range
- AA US Officer -suppression aura
I like building around gimmicks, if you couldn't tell. What I'd really like from Relic, though, is making most bulletins worth a damn. I like bulletins that do new things, like the AFO artillery range or giving the ostwind hull MG suppression.
Those all sound good, I tend to stay away from the +% Armor and Penetration ones (though someone crunching the numbers to see how that translates into bounced shots would be interesting.) The KV-1 "Defense %" is another weird one... is that HP or what? Lol
HMG Accuracy Vs. Suppression % Vs. ROF is another interesting question as to what increases Pin Time and/or damage the most.
A really neat idea would be to introduce "Epic" bulletins that would do gimmicky stuff like add minor doctrinal abilities to stock units. For example a Rifleman bulletin that would let them place M7 light mines without Infantry company. You'd need to limit them of course to avoid borderline-OP ones like giving REs demo charges.