Dominion: How to Deal With a Board Filled With Terminal Actions
A high money:action ratio is definitely required with an overabundance of terminals. What ratio is appropriate will depend on which of those terminals you decide to use and if/how you're being attacked. Generally it's better to err on the side of too much money; people aren't usually disappointed by a hand full of Silvers, and you won't bore your friends taking time to decide which 1 of 3 actions to play. A slightly augmented big money strategy is often very competitive in the absence of an engine.

If your hand will be small (due to, say, a discard attack and not much card draw available), you can risk having more actions because they odds of collisions are lower. In a >2 player game where you think Militia is likely to be played between almost every one of your turns, you could probably do nearly a 1:1 ratio of Militias and Silvers until you get to Golds. Games like this often end on piles, so getting an extra buy and starting early on Duchies is probably a good idea. (If you're discarding cards anyway, they might as well be points rather than money.) Also realize that in games with more than 2 people, joining in on attacks is less mandatory. If both other players are snapping up the Militias, you'll be better off letting them attack each other and instead getting a card that actually benefits you (e.g. Navigator).

On the other hand, if you are trashing or drawing a lot, you should be buying more money. If one of your terminals is Council Room, that means you're drawing 4 cards and hoping none of them are actions. Even if your terminal only draws 2 cards, if you've gotten rid of your Coppers, you need to be buying Silver and Gold to make sure your deck has enough money cards. "Doublejack" where the only non-money cards you buy are two Jack of All Trades is incredibly good because it trashes, draws, and helps you treasure-up all at once (not to mention it's extremely resilient against attacks). And you only need 2 Jacks to do it.