Yes, Iran should be sanctioned for its nuclear program, because Iran's program is a threat if it develops nuclear weapons. Iran is very close to having nuclear technology. Iran wants to use that technology against its enemies. Iran needs to be sanctioned now, because its program can be kept in line now, before it gets out of hand and even more dangerous.
Former Iranian President Mahmoud Ahmadinejad constantly said Israel should be destroyed. Despite recent attempts by the new president to ease the strain caused by his predecessor, Iran still should be considered a threat to start a nuclear conflict until the country is more open about is reasons for attaining nuclear technology. Iran must have more international monitors from the United Nations before it is to be trusted. Until then, sanctions should still be in place even though Iran's threats against Israel are technically a regional dispute and not an international one.
Who is the only country that has ever used a nuclear bomb- twice? The United States. Iran is not developing a bomb. The Supreme Leader even came out and said it is a sin to develop and store these types of weapons. If they do use it, hypothetically, then the Supreme Leader would have to step down and a new one be elected. Even if you believe they are really hurting Iran, Iran is now becoming proficient in making and producing its own materials rather than relying on other countries.