I think it is worth GM talking to sponsors when they are arranging adverts to give advice on what works and what irritates, perhaps they do and it just gets ignored. The current TM advert folds down and annoys, I gave up being on the forum one night as I could not use my tablet as the fold down was constant no matter how often I closed it. Whenever an advertiser does a fold down down advert it always gets a thread with complaints and that can't be what they are after.
Had the banner remained unfolded I think it looks very smart and works well. Keep banners, stop them unfolding.