The yeast does have something to do with it. The weizenbock uses the bavarian weizen yeast and therefore has those banana and clove esters. The wheatwine would use a cleaner (less estery) yeast. Also, a weizenbock is lower in alcohol than a wheatwine. A better way of looking at a wheatwine is to think of it as a barleywine with much of the malted barley replaced with malted wheat.