Avoid #2 at all costs. Nothing drives me away from games faster than "Please wait X time (or pay more money) before you can continue playing," whether it's a daily action limit, or some kind of "endurance" hack, or whatnot.
You want people to invest themselves in your game, and being multiplayer having more players online at once is only ever a good thing. Turning away players is counter-productive.
Notably, the designers of KoL have also abided by that -- your actions per day are limited, but there's no way to directly turn real world money into more turns. (There are indirect ways, but you can almost always get them cheaply with in-game currency as well.)
You want people to invest themselves in your game, and being multiplayer having more players online at once is only ever a good thing. Turning away players is counter-productive.