Hello Charles,
It seems like things that are trivial in C are often difficult in the graphical environment. For example, it is possible to search through a short delay for some event (such as a maximum or a zero crossing), but it gets rather cumbersome -- see http://ez.analog.com/thread/18706 . On the other hand, SigmaStudio makes it easy to construct rather complex processing flows without writing a line of code. Although originally intended for audio post-processing, SigmaDSP has found some quite novel applications.
Judging from what smartphone apps are doing, ARM processors are capable of much more than Sigma DSP -- for example, decoding MP3s and FFT spectrum analysis. If you need a dedicated DSP of greater power, perhaps a Sharc or Blackfin would do. SigmaStudio for Sharc allows you to build custom functions in C, then embody them as blocks in a SigmaStudio project. This could provide you with the best of both worlds.
Best regards,
Bob