Sounds like something probably shorted in the motor and contributed to the ESC frying. On my AE2 I ran a 35t on 3s and now I'm runing a 55t on 3s along with a Castle 10a BEC. Mine is 3 years old and still going strong.

Pick up a Sidewinder 3 to replace it, it is water proof and can run brushed or brushless. Alos get yourself the Castle Link so you can easily program it. You will also be able to use the castle link to program your BEC.