I totally agree and understand.
I will happily give you the code, but here are my concerns
1. It is not AMD style. The original viewer was released at 1.6 and has never been updated. I have been patching it along, badly. It functions at 3.4 but I have not tested it past that. Taking it to AMD style would be a ridiculous amount of work, which is why we deprecated it
2. I have alot of stuff hardcoded into to make it work. Back in the 1.6 days alot of functionality (like legends, etc..) didnt exist. We wrote a lot of code to custom include that, and dropped it but didnt always clean up the code afterwards
3. It doesnt work on mobile devices
4. It doesnt work AT ALL on touch devices. In fact, its a disaster, hence deprecating.
5. There is alot of code in there to make it work on IE6 (which we finally dropped support for last year)
6. Its slow as dirt
Your call. Our new viewer is way better, and I am excited to see what ESRI comes up with (would be nice to be in a supported environment, so to speak)