When you say S3 you have to be more specific. In the US we only got a dual core CPU because the quad used across the pond doesn't play nice with LTE chips. Those overseas have a completely different chip in their S3's.
This does look to be a potential game changer. Biggest downside of LTE has been battery life. If Apple has managed to design a chip that increases performance double and still dramatically reduces power consumption then that is what I would call a game changer. They've peaked my interest.
That said, I really don't use the CPU that much on my phone. It seems the data pipe is the congestion point, not processing power. LTE certainly has the potential to change that, if I ever get it.