Reading between the lines. x32 is primarily about Android on Atom.
x32 is primarily about code bases that are not 64bit clean so you need a 32bit userspace.
x32 is about the fact that Atom is an in order processor unlike the rest of x86 that is super scaler and out of order. To keep a processor like Atom busy you have to have your instructions in a good order in the instruction stream and to keep your instructions that way you need more register names, to avoid spilling to memory.
Given the push towards power efficiency we may see more limited x86 cores like Atom targeting the embedded space. So I expect x32 may have a long life if x86 as enough adoption in the embedded space.
x32 in general? Ridiculous. 32bit pointers are just too small and I fail just at the moment when you are doing something interesting in your application. A few percent better performance is not worth the risk of application that don't work.