If Obama was going to impose more gun control, it would have happened in his first two years when he had the House on his side.
I'm not going to say you're wrong with this, but there's no way you can know this is true. Obama had other "headlining" issues in his first 2 years that were more important to him. We know the D platform wants more gun control. Obama himself, as recently as debate 3 (EDIT: I think it was actually debate 2) said he wants more gun control. While I'm in the camp that says it will be very difficult for him to get any gun control legislation passed due to the fact he doesn't have control of the House, it certainly isn't impossible. It could be as simple as an ammo tax rider (or anything, for that matter) attached to some piece of legislation the republicans want passed.
To say that he won't do it because he didn't do it earlier is false security. Just remember what happened when our military leaders believed the Viet Cong wouldn't attack on Tet, because they hadn't done it before. We know what he believes. We know what his party believes (for the most part). If he wants something passed, there's 1001 ways for him to accomplish it.
I do not believe the sky is falling, but we shouldn't let down our guard because he didn't do it when the D's had control of the house.