Bibi's Problems

Shmuel Rosner does a good job of outlining them:

Avigdor Lieberman: There is no coalition without him. And since Lieberman’s ambition doesn’t stop at the Foreign Ministry, he will be the one to decide when to end his partnership with Bibi. Another problem with Lieberman: he likes to annoy people, especially Israeli elites. This will not help Bibi in his quest to rule from the center.

Strong opposition: Tzipi Livni got more votes than Netanyahu, and will be ready to do it again to take his seat. This means that the Israeli public will be able to replace Netanyahu should it so desire. Ariel Sharon was a strong prime minister for many reasons - one of them was the perception that there was no one around even close to being a satisfying successor. Netanyahu will not enjoy such a luxury.