That is the primary contribution of a complex carb in those gels (except for Clif which uses brown rice syrup). You might want to add a simple sugar in there like dextrose or fructose. I think on the Gu site they aim for 80% complex/20% simple but I haven't read the literature to know what they are basing those numbers on.
You may want to consider a source of getting salt/potassium as well.
May I ask where you got your maltodextrin from? I am testing out my own gels and drink mix and have been unable to find it locally so far.