I am in principle opposed to conscription since it constitutes forced labor, or to be more blunt slavery. But as the great Ludwig von Mises pointed out, if the protection against foreign totalitarian rule requires it, it can perhaps be justified in some circumstances since freedom from totalitarian rule might be dependent on it. And in the case of Israel that was for long not an entirely unreasonable argument, given how much bigger the population controlled by enemy governments were.
However, there is simply no invasion threat to Israel right now. The two main invasion threats to Israel have been Syria and Egypt. Syria is a big mess with the government being busy maintaining control of the small fraction of the country it still controls and the rebel groups (including the Islamic State and al-Qaeda (Nusra)) being busy fighting the government-and each other. Meanwhile, Egypt is controlled by a relatively pro-Israel dictator, dependent on the U.S., who is more hostile to the Hamas government in Gaza than to Israel. Which means that there is no need for large numbers of ground forces, and therefore no need for conscription.
Israel still face the threat of missile attacks, from various groups, but that should be dealt with by improving and increasing missile defence systems like the Iron Dome, David Sling’s and Arrow systems, and strengthening the Israeli air force. And in general by improving military Israeli military technology, not forcing young Israelis to unnecessary forced labor.