The_Man, not only video editing, but a lot of other applications are highly benifited from a quad core processor compared to a dual core one. The best example is Adobe Photoshop. It is a software, getting used by almost everybody in some extent. It is highly multi-threaded and take the full advantage of a quad core CPU.
2ndly it will help you to enhance your productivity. From Matlab, dot net to even Microsoft Office. Even the current generation Antivirus software like AVG are tremendously benefited from a quad core CPU and customers are often asked to invest for a processors having as many CPU cores possible.
The 10 FPS difference is the best case scenario, it is not 10 fps higher all the time. In 90% cases it is not over 6 fps.
just for 6 fps average, are you going to sacrifice the benefits of a quad core.
2ndly Tomshardware does also have 2 articles, CPU/GPU bottleneck story. muticore CPU also reduces the chance of bottleneck of GPU.
Read the part 1 and part 2.
It clearly says that in current generation games a Tripple core is required in more than 90% cases to avoid bottleneck when paired with a decent set of cards. So don't you think all games that will be released within 1 years need more CPU cores?