Not at all.
A CPU featuring more cores like an i5-3xxx would be a great increase of performance. But don't get fooled by cores only, because single-core performance is very important. Intel has the best single-core performance and therefore they have the best performance in gaming, because a lot of games mostly utilized 2-4 cores. Getting the i5, would get you to the sweet spot, because it has the most mainstream number of cores.
But getting the better CPU wouldn't get you anywhere, if you didn't upgrade the GPU as well.
I don't know you budget or anything, but the least I would recommend for gaming is a GTX 650 or a Radeon 7750. Those two GPUs would let you play the latest games at low details at decent framerates.
However, if you don't aim above a GTX 660 or a Radeon 7870, then the i5 makes no sense. Then the current CPU you got now would serve you fine. Though you might experience some bottlenecking in the latest games that utilize more than 2 cores.