Honestly, unless you use French Resistance with Joint Strike to make a liberation attempt even worse odds, it’s pretty useless. Even with them used thusly, they are pretty useless.
Mideast Oil can be okay. Decent for getting fighters from England to Japan fast, but honestly, again we’re not talking about high powered utility.
All in all, I have to say the MAJORITY of Allied National Advantages suck. Especially compared to Axis ones. (in both LHTR versions. OOB is a different animal.)
As for number of NA’s per side, generally speaking the tournaments that I play in have 3 for Germany, 3 for Japan and 2 for each England, America and Russia.
With those numbers, we’re talking bids for the axis in the amount of 0 to 2 IPC. I’ve even bid for the Allies with those numbers because the Axis have a better assortment to chose from. Especially since they are randomly selected (2 random per nation, one chosen by Germany and one chosen by Japan.)
Salvage I’ve used once or twice. It usually only works when defending Moscow. Otherwise, it’s EXTREMELY rare for Germany to lose a tank and not take the land.