I think you are missing some points here.
1. The pi runs linux. You can use c/c++, python, perl, bash scripts, almost anything else you want
(1a). You have hundreds of libraries to go with that. Also thousands of programs to pipe info.
2. You can connect a 3g, wifi stick or anything USB instantly
3. You lose absolutely no time on hardware design. It might just be me but I like have my hardware done and just worry about software
4. The community will point out almost all the hardware/software limitations or bugs of the pi and you know in advance what you are getting yourself into
5. You have portable code. If you program for linux, it runs on most hardware that runs linux (some recompilation required)
6. The community has started building addons (see arduino shields) which can achieve much more
As a software developer who used embedded linux and arduino class hardware, I love the pi because it solves all the problems I don't want to worry about. I also love that I don't have to test it on different hardware/software configurations. My target will always be raspberry/debian. I undestand that this is not what some people want/like but for "rapid" embedded development the pi is number one and because of its community I think it will be for a long time to come.