As others have noted, you can easily shim the shimano brakes, either by buying the shim they sell or by inserting something in the hole created when you depress the brake levers (such as a piece of felt- floor protectors for furniture work well and have adhesive to make them stick).

Also, you can switch your bars to smaller reach bars. I have elf bars which have about a 2 cm shorter reach than my previous salsa poco and deda bars. Smaller reach to the bars means you can reach a little more for the brakes.

Another factor-- shimano brakes have quite a lot of resistance. I now use sram brakes and find them easier to depress. Rival 2009 will also have an adjustable reach (when available) and Red already has that feature.