Edward Snowden should not need a pardon. His only crime has been to expose government abuse and corruption. Therefore, instead of pardoning him, he needs to be protected under the law as a whistle blower.
Also, he should be allowed to testify to Congress about the systems he's been in contact with in front of congress.
The snooping tools being used by the NSA, FBI etc should not be hidden from the people. Remember that often quoted phrase used by multiple founders of our country:
Those who would give up Essential Liberty
to purchase a little Temporary Safety,
deserve neither Liberty nor Safety.