Anderton
I wouldn't mind having the option to create feedback loops. That said, when I need feedback, I use the external insert plug-in and patch an output back into an input. That's how I did it before computers existed, and was the basis of my looper application for SONAR.
Then again, we ARE in the United States. The first time someone blew their speakers, they'd probably sue Cakewalk for a million dollars saying their hearing had been damaged permanently, and Cakewalk was negligent in not preventing feedback 
They have many ways to damage something, including your external scheme. And there is easiest way to prevent it: auto-mute if sound's level exceeds some threshold. And other DAWs do it, and nobody sue them. And nobody sue delay plug-ins developers, and some of them have crazy settings that could self-oscillate pretty easy. So your arguments don't work, in real life there is no problem with feedback loops, it is imaginary problems.
And you always say that if some missing feature has a workaround, it should not be implemented primarily. I think quite opposite. If there is workaround, it should be implemented in first of all. And there are the reasons:
1. If there is workaround, it means that there are people who use it, so new feature would be used too.
2. If there is workaround, it means that it is easier to implement, because developers would exactly know what to do.