I don’t know if it’s deliberately treason and he should be tried on the possibility, but he let his own personal philosophy guide him in his actions, which resulted in 1500 Israeli deaths.
Definitely, he should be forced to go to the front lines.
You are correct that one cannot be certain until after a trial, but the fact that observations during several months prior to the attack were repressed (and not only junior military observers but also civilian observers) makes it hard to see this as just a big mistake.
Haliva was left out of the emergency war meeting that happened as soon as news broke. Everyone at the top level understood immediately his culpability, and Haliva himself understands he’s done.
Here’s a relevant excerpt from the article:
…All of this would be bad enough. But it becomes even worse when seen in the framework of the 10-month insurgency the Israeli left waged against the Netanyahu government.
That insurgency was led by Haliva’s family. His ex-wife and the mother of his children, Shira Margalit, is married to Ilan Shiloah, a senior advertising executive. Margalit and Shiloah stood behind much of the political unrest that Israel has experienced since last year. Haliva’s daughter spoke at anti-government protests. His son’s twitter feed is filled with anti-Netanyahu invective...