I assume the weak link is the Kahanist group right? Bibi, for all his flaws, is merely a rightist machine politician who prefers to wear many hats: how much can he really capitulate to this group?
It isn't a moral thing of course, but he doesn't like his hands being tied (more accurately: he doesn't like the sense that they might or could be), and that's more of an issue when you're the largest party in a narrow coalition that you don't absolutely dominate in terms of seats than any other situation. There's also the issue that he doesn't like other parties or alliances on the Right getting too big: one of the big themes of Israeli politics in recent decades (and one of the big reasons behind its instability) has been him trying to get this or that party or alliance up to a certain size because more seats is good and then deciding that they have too many, that that's a threat to his authority, and trying to crush them.