I don't know if I agree that any mainstream eschatological theory is "heresy". I don't consider these issues "central" to the Christian Faith, but more on the outside circle of debate. That is why there are so many different points of view regarding the end times...even good Christians disagree on them. :)
Hyper-preterism (sometimes called full-preterism) is NOT a mainstream doctrine.
Hyper-preterism is an heretical doctrine, in that it is a belief that all prophecy was fulfilled in the A. D. 70 destruction of the Temple -- including the second coming of Christ, the resurrection of all of the dead, the Final Judgment, and on and on.