Sometimes, Wikimedia should just ignore the editors
Imagine if the design of a website was solely decided upon consensus of the writers. Imagine a newspaper or magazine where the writers get the final say, how would that look? It'd consist of massive blocks of text.
Editors rebelled against the use of infoboxes, these summarised key facts about the subject in a box out. Their argument was that if you wanted to know the place of Bach's place of birth, you could drill down and read their wonderful prose. But no one cares about your wonderful prose when they just want a fact. Google has all the data to know exactly what a reader wants, so search for Bach, and Google's Knowledge Graph gives you the key information on the right.
The new image-viewer is made for readers, not editors. If editors don't like it? So what? Wikimedia shouldn't be asking editors, it should just be looking at data, it should be doing A/B testing. What are the engagement figures? Are people looking at more images? Just release that data and shut everyone else up.