Small cabins are usually the best. Getting upstairs on a 747 is grand. For many years SAA had them as Y and it was a real bonus if you could get there. They may still do this.
I fail to see why anyone in management think it is worth the engineering cost of moving the cabins around. Even presuming that it was done at a C or D check, so that the a/c was not off line specifically for this task, there is cost and risk.
You are going to pull equipment and cables around, probably break something, panels that are taken down will not go back up as expected etcetera - the usual things that you would expect with this kind of redecorating. And just how much extra money are they going to get for this? What is the payback in months or years? I suspect that the payback cannot be identified as they will 'think' that pax like it more and customer service questionnaires will ask the right question to 'prove' that pax like it.
Sounds like a waste of time and money to me!
Once again Mr Vonnegut's statement is apposite ...
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"I tell you, we are here on Earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut, Jr.