I haven't checked your math, but you have the psychology right for MMOs. Basically, figure out what the Flavor of the Month is, and then play what counters it.

See Dave Sirlin's discussions of yomi layer 3 and rock, paper, scissors.

Yomi is the Japanese word reading, as in reading the mind of the opponent. If you can condition your enemy to act in a certain way, you can then use his own instincts against him (a concept from the martial art of Judo). Paramount in the design of competitive games is the guarantee to the player that if he knows what his enemy will do, there is some way to counter it.

What happens, though, when your enemy knows that you know what he will do? He needs a way to counter you. He's said to be on another level than you, or another "Yomi Layer." You knew what he would do (yomi), but he knew that you knew (Yomi Layer 2). What happens when you know that he knows that you know what he will do (Yomi Layer 3)? You'll need a way to counter his counter. And what happens when he knows that you know....

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Before we get into how ordinary human minds can become entangled in complicated guessing games, let's look at what needs to be there to create these guessing games at all. The designer's tendency might be to create moves and counters. Then create counters to counters, then counters to counters to counters, then counters to those, and so on. Actually, a game need only support counters up to Yomi Layer 3, since Yomi Layer 4 can loop around back to Yomi Layer 0.

Let's say I have a move (we'll call it "m") that's really, really good. I want to do it all the time. (Here's where the inequality of risk/reward comes in. If all my moves are equally good, this whole thing falls apart.) The "level 0" case here is discovering how good that move is and doing it all the time. Then, you will catch on and know that I'm likely to do that move a lot (Yomi Layer 1), so you'll need a counter move (we'll call it "c1"). You've stopped me from doing m. You've shut me down. I need a way to stop you from doing c1. I need a counter to your counter, or "c2."

Now you don't know what to expect from me anymore. I might do m, or I might do c2. Interestingly, I probably want to do m, but I just do c2 to scare you into not doing c1 anymore. Then I can sneak in more m.

You don't have adequate choices yet. I can alternate between m and c2, but all you have is c1. You need a counter to c2, which we'll call c3. Now we each have two moves.

Me: m, c2 You: c1, c3.

Now I need a counter to c3. The tendency might be to create a c4 move, but it's not necessary. The move m can serve as my c4. Basically, if you expect me to do my counter to your counter (rather than my original good move m), then I don't need a counter that; I can just do go ahead and do the original move...if the game is designed that way. Basically, supporting moves up Yomi Layer 3 is the minimum set of counters needed have a complete set of options, assuming Yomi Layer 4 wraps around back to Layer 0.