I really love this program and all but i think it would be very usefull and helpfull to have some sort of explanation of the grammar. just a page or something where it would be explained and different charts shown. That way we could learn not just how to speak the language but how it actually works as well!!!!
You are not the only one to think so :-)
However, it is never possible to provide everything at once. People are asking for different stuff: more languages, grammar explanations, better forum, better translation section, better mobile app, better vocabulary...
Some German lessons already have grammar introductions and you can always post your questions about tricky points you don't understand. This is hardly enough, but you should know that Duolingo on itself as it is now is not a comprehensive learning tool. It is great for learning words and phrases, and I find it invaluable for drilling German cases and word order. However, if you are serious about learning the language, you should find a good grammar guide (or at least search for explanations when you need them), listen to some audio content recorded by native speakers, practice speaking or corresponding with other people in the target language. Don't limit yourself to Duolingo alone.