I think it would be a damage to Wikibooks brand when different language editions would introduce different logos. We have to make decision together.
Looking at Wiktionary case, which has similar logo vote at the same time as us, they seem to be in similar situation. The logo has been chosen but no one is eager to replace the old one. My personal view is that both communities - Wiktionary's and Wikibooks' - have decided to simply ignore results of the vote as they feel this hasn't been their vote. People having nothing to do with these projects were leading discussion on new logo and voted for it.
Personally I find chosen logo a peace of rubbish, complete amateurish work and a complete mistake, having nothing to do with a professional logo. It looks like it was drawn by a child with crayons. If you compare it with logos of Commons, Wikipedia or Wikisource, it becomes clear that new logo does not represent the same level; it's in kindergarten of logo making.
Beyond my personal looks: it's not fair to change rules during the game. People have chosen certain design: with Wikimedia colours. After changing colour version, the logo became another design; thus, the vote should start again. Currently the status quo shows: practically no one is interested in introducing new logo. New logo is defunct, has not gain acceptance and the vote should start again. With more serious candidates.