I’m a fairly new player and, while I lack your experience, I have put some thought into the matter of progression vs resources and generally agree with your conclusion.
Unfortunately, I believe the shortage of gold was intentional; the ability to convert Mercury into gold was likely meant to cover the gap as well as generate an income stream. I can’t say I’m fond of that, but it’s common enough in F2P games.
However, assuming we wish to tweak the economy so that alchemizing Mercury into gold wasn’t necessary (leaving Mercury the province of skins and similar cosmetic goodies), increasing the amount of gold by (x)% for the Raider pool and (2x)% for the Antagonist pool as well as lowering the amount of Faction points by at least a third for both would change the current dynamics.
Why lower Faction points? You may need a lot to reshuffle or lock cards, but with gold at such a premium you can gain enough Faction easily since you won’t be forced to split your earnings. Like I stated initially, however, I don’t have much experience, so my argument here may be flawed.
For a deeper change, not offering the missions a la carte for gold would reduce demand slightly, at least I think so. However, keeping the “mission of the week” is fine, though depending on how many campaigns get released a “campaign of the week” idea might be better. Furthermore, for those that have invite tickets, perhaps allowing them to be used on an entire squad of people during matchmaking (in other words, you’re not bringing a friend along, but extending the invite to random Raiders) would be interesting. I have tickets but nobody to use them with. Invites would earn gold on success or failure, and Mercury on success.
These are just some thoughts I had; I personally think that only the primary idea of adjusting the faction/gold ratios could be implemented without very serious analysis, but perhaps the rest may be of interest.