This guy has been retired for 5 years. Despite being a former chief, he's not at the helm of the security forces and I'm pretty sure he doesn't have access to the latest intelligence. Even then, he said the "breakout time to the bomb under the terms of a possible deal" stated by Netanyahu was bullshit, not the fact that Iran IS working towards a nuclear weapon. He added:

He stressed that it would be “almost impossible for Israel” to live with a nuclear Iran, and that if there was no alternative to military intervention to thwart Iran, “then we’ll have to consider it. But I don’t think we have reached that moment.” He said “there are ways” for Israel to thwart Iran.

Dagan, 70, also that said he had feared Netanyahu would launch “a military operation” against Iran during the period when he served under the prime minister, despite the fact that all the heads of the security services opposed such an action. Even if successful, said Dagan, the operation would not have set Iran back “for very long.”

He knows what Iran is up to... Of course he does, he headed the agency responsible for assassinating Iranian scientists and developing the most sophisticated cyber weapon ever, specifically targeting Iranian nuclear facilities, he just disagrees on when and how to deal with it. When are people going to deal with the actual point of Netanyahu's speech which is how the "deal" gives practically Iran the green light in ten years time?

Also, people calling Netanyahu a "psychopath" and a "warmonger" yet the ex Mossad chief criticised Netanyahu for failing to defeat Hamas in the Summer which would have required a large scale invasion which would have caused MUCH more destruction and MANY more deaths:

Castigating Netanyahu’s leadership in other areas, Dagan — who has frequently criticized Netanyahu since retiring — said Israel should and could have defeated Hamas in Gaza last summer and enabled Palestinian Authority President Mahmoud Abbas to reassert control of the Strip.