It really depends on which laptop Dell is offering you. You can argue that you are concerned about the difference in clockspeed. Without knowing anything about CPU architecture advances over the years a 700MHz difference would seem to be a huge difference in performance. Perhaps the may offer the i3-3227U instead which is 100MHz faster @ 1.9MHz. That would make it equivalent to a 2.48GHz C2D CPU. But that will only happen if it is one of the optional upgrades.
In terms of video editing, you should actually see an improvement in performance. The Core i3 has Hyper Threading (HT) which can improve performance as long as the video editing program you use can take advantage of HT; most current ones can. The performance increase depends on how well it has been implemented. It could be anywhere from a 10% - 40% improvement compared to a CPU without HT.
Photoshop does benefit from HT as well as shown in the following benchmarks. However, not sure about Corel Draw.
http/www.anandtech.com/show/2832/11
As it stands, it does seem that the Core i3 should provide you equal if not better performance than your old C2D CPU as long as Hyper Threading can be utilized.
If you encode DVD movies or Blu-Ray movies using the x.264 codec, then you should read the following linked article about Quick Sync which can improve encoding performance as long as you use a video encoding program compatible with Quick Sync.
http/www.anandtech.com/show/5771/the-intel-ivy-bridge-core-i7-3770k-review/21
All in all, I think you are getting a more capable laptop with the i3-3217U CPU. Of course if you can manage to get a better CPU (if available), more RAM or larger capacity battery (if available) by playing dumb, then all the better. Of the three a faster CPU is generally preferred because that is the single component you will likely not be able to upgrade yourself. Plus even if you could, it would be the most expensive component to upgrade. RAM is the cheapest to upgrade yourself.