You Lose If You Get Checked

In other news, I retract my opinion on 1. e4. I got brutally slaughtered against TChosen after playing 1.e4.

Actually, I think it's just because I suck at this variant.

no im pretty sure 1.e4 is a forced win.. well nevertheless im pretty sure that 1. Nc3 is not the best move

There is a variant called three-check chess. You can guess how you win. [By checking the opponent three times. Not necessarily in a row.]

I agree knights seem overpowered. I suggest a new rule: Knights can't jump over pieces. They have to move in an L shape that does not go through any pieces.

On the other hand, you can remove the knights entirely. I think the queen might be ridiculously overpowered as well though, so if there's a piece we are removing it should be the queen. Perhaps replace her with a commoner?

You could weaken the knights slightly by copying the equivalent piece in Chinese chess (xiangqi) - the knights move on the same L shape, BUT need one square free in front of them for a run-up. ie, initially the knights can't move. If you move a pawn one space forward they have the run-up, and can jump. 

Initiative is overpowered. This is a forced win in 5.

Now I will go through all the variations:

We have established that 1: ...e6 and 2: ...ke7 are forced. Now let's examine move 3.

By the way, if you are up for ridiculous variants, one of the stupidest ones I ever made was an entire army vs. a knight that moves three times or an entire army vs. a king that moves 3 times. Both are equally unbeatable.

Squares controlled by a knight that moves thrice:

Good idea, nice way to revive the thread. 

Xiangqi is really fun by the way for anyone who hasn't played it.