I'm not sure I saw it in the base image, but shouldn't it be there? A type 3 UUID for example needs that code and perhaps using the hash for random numbers might be better for type 4 UUIDs.
Squeak has DSA in the image. I dunno why DSA was chosen over MD5 -- if the uses of DSA can transfer over, still, then it would be nice to switch.
Otherwise, MD5 is certainly widely used, so having it handy would be nice. Modules are gonna be here any time, now, anyway, right? So the bloat won't hurt as much.
-Lex