How is Baun different?
The problem with both Kikaha and Tull is that they were VERY underdeveloped as actual linebackers. They were essentially small DE's. Both also had considerable issues with injuries (both were coming off injury when they were drafted). Kikaha actually was surprisingly good against the run as a 3-4 OLB but then the injuries began to mount. But he wasn't athletic enough to be useful in coverage.
Baun is a much better prospect. Certainly, he can still bust. But he proved more as a traditional LB than either guy, and was significantly better in coverage. I do questions his instincts as a stand-up LB and his ability to shed blocks. It's something that is a bit difficult to determine by looking at the available stuff on YouTube. But at least he has positive traits. He looks smart, hardworking, is a natural pass rusher, and looks very capable at dropping into coverage (probably one of the better LB's I've seen in this role, and I looked at about 20 LBs from this class). I'm hoping he's not a liability against the run and he is over his injuries a few years ago, because that is what is going to make or break him.