"a few years ago having a huge banner was a big no-no in UX"
Is there anything that has happened between then and now that undermined the reasoning behind that proscription?
I would not judge smaller versus larger banners just on how many giant banners are in the wild. That could be due to many factors other than UX considerations, with the most likely one being that bigger images seem prettier. It may be that prettier is slightly more likely to get a user to stick, but that is probably the extent of it.
Unless you are mostly concerned with advertising the show, some of the space is better used in your current design. ...or, if some of those elements are not seen as valuable, could be put to use for new elements rather than making what is already the largest element even larger.
One more point: With a large banner you want to be particularly wary of putting it right at the top. (Or...To state this a little differently, for a top banner, you want to be particularly wary of making it large.) Doing this makes it take much more time to find any other information, including pushing some elements off the screen and necessitating scrolling to reveal them. (In fact, for smaller screens or windows you may even push some of the image off the screen!)
(My vote: The current design, where the image size is plenty, at roughly half of my browser window after my browser chrome and the upper elements of your site.)