I know Shamir is often criticized by the right for attending the Madrid Conference. The fact is that while he attended Madrid, he did not give away anything there, and in fact later disclosed that he had no intention of giving away anything. Some say he set a precedent by sitting down with the so called Palestinians.
I saw the late Meir Kahane, in person and heard with my own ears, in 1976, him discuss the issue of peace conferences. He said it was fine to sit at a conference and go through all the nonsense for months while Jews tightened their hold on the Land of Israel. He noted that the recent (at that time) Vietnamese peace talks spent months arguing over the shape of the table. He also said that he would happily sit down with Yasir Arafat, or George Habash, in a conference but he would tell them his view of things not what they wanted to hear. In many ways Shamir did that. During his reign Israel firmly ruled Judea, Samaria and Gaza. There were certainly no Oslo type moves. Every Prime Minister since Shamir gave up land and retreated.
Rabin,Oslo lost Gaza, Ramallah and other West Bank cities, heavily armed savages
Bibi-Wye accords basically lost Hevron.
Barak-Southern Lebanon, tried to give up Judea, Samaria, Gaza and Jerusalem.
Sharon-Destruction of Gush Katif
Olmert-offered to give up everything that isn't nailed down. Brutally evicted Jews from Amona and Peace House in Hebron.
Looking at this history how can we not long for Shamir? Not to mention Shamir even voted against the Sinai withdrawal as a member of Begin's government. Even better he was a low key leader who was not a lightning rod to cause criticism of Israel as Begin and Sharon were.