Eh? It's a redundant block, because you can nest FOREVER and IF, but there are lots of redundant blocks, e.g., NEXT COSTUME. I don't know if we have a "worst block," although we did for a few days when Jens squeezed two entirely unrelated purposes into one STRETCH block, but I made him fix it very quickly. :~)
I'm very sympathetic to the felt need to get the appearance of blocks just right; I'm the one who made Jens reimplement the Scratch loop arrow for C-shaped loop blocks, which wasn't in Snap! for a long time, because I find it such a wonderful example of the careful attention to detail in the original Scratch design. So, yeah, I expect we'll get around to this someday. But of course it's just a cosmetic issue, and I guess also a pedagogic issue if you're making blocks for other people to use. It'd be much more serious if we had cap blocks and not stack blocks!
(P.S. An example of not exhibiting careful attention to detail in Scratch is the use of the terms "hat block" and "cap block" to mean two different things! It took me forever to understand that when people talked about cap blocks they didn't just mean hat blocks. Can we call them "foot blocks"? Or "smelly sock blocks"? Or something?)