Hmm....personally I would shorten the cooking time. This was my first time so I used the toothpick testing method. The other banana recipe I did before actually baked the whole 50 mins and was not dry, so I didn't think 50 mins. would be too drying for this one. The banana flavor was not too strong, so I may go with Wolf's suggestion by adding more bananas. And shorten the cooking time too!
Whenever I bake brownies and chocolate cake (from mix, hihi), I usually shorten the cooking time and that would make them more moist.