eddieroolz :
A good idea, as long as the code size is kept in check. Remember Microsoft, most phones only have single-digit GB worth of storage.
Well it's not MS's call but the software programmers. Dual binary works by compiling the code twice, once for each target architecture then putting both compiled binary's into the same file. RISC binary's tend to be bigger then x86 but not by much. In essence instead of a 1.5MB executable file for each platform you get a single 3.0MB executable file that works on both platforms. The data files should remain the same size though.