I think that there should be gender of nouns in the vocabulary next to the word which is learnt with every lesson, so that one doesn´t have to click on the word in order to check. so, for example instead of just writing "zug", there should be "zug(m)" :)
I agree that adding gender to nouns in the Vocabulary screen would be very helpful. When learning German at school, it was always drilled into me that learning nouns without their gender was useless, since they can't then be used properly. Using the incorrect gender has been one of my most frequent mistakes while practising German here.
i haven´t checked the discussions (obviously:D), but it is kind of a nonsense that you have to click on every word to see gender.. and yes, it definitely wouldn´t be a bad idea to show a plural also. perhaps if they see that more people ask for the same thing it would make some difference :)