The two primary problems with the pre-1967 borders were the Golan Heights (part of Syria) and the narrow corridor through Jordan that contained the road between the coast and Jerusalem. Both of these were used as bases for attacks on Israel proper. As a former artilleryman, I can tell you with some certainty that firing from the Heights (and I've been there) would add at least five miles to the range of any artillery or rocket being fired south or west. Another issue was the denial, by the Jordanians, of Jewish access to the Temple Wall (Wailing Wall) in the Old City. It is easy to say that good will can correct these problems, but, IMHO, the Israelis would like some guarantees.