The only way you may have noticed this improvement is when you hit the limit with PSoC Creator 2.0 before and tried the same project with higher speed again using Version 2.1. This change may not seem important until you hit the ceiling and suddenly there is nothing more important than the increased speed of a peripheral.
The new version if PSoC Creator offers improvements in 2 major categories:
Version 2.1 is easier to use with features like rubber banding and the new document manager
It generates faster hardware implementations using the same silicon by using improved routing
If you have not upgraded to PSoC Creator 2.1 yet, think about it, there are so many improvements waiting to be explored.