Yes, this is largely inspired by Miro (actually, it was called Democracy TV back then), and by PenguinTV. The major differences with KatchTV is that KatchTV is designed for KDE, and KatchTV has multiple channel guides built in. KatchTV also takes advantage of advanced KDE technologies like KHTMLPart (the browser engine that makes Konqueror go) and the embedded media players available within KDE.
If you're asking I wrote KatchTV instead of just improving others... well, I did submit some improvements to PenguinTV. However, PenguinTV was more like a download utility than a viewing application, and so what I wanted to do with it would have been outside of its intended scope.
DemocracyTV (aka Miro), on the other hand, was much closer in design to how I thought an ideal Internet TV app should look. However, it was so slow, clunky, crashy, and unintegrated at the time, that I didn't feel it was a good base to start from. Time, and lots of effort by the Miro team I imagine, have since proven me wrong. At least on OS X, Miro is a nice, fast, fluid application. It still has easily discovered bugs, but nothing particularly noteworthy.
That all said, I believe KatchTV still has a lot to offer, especially for KDE users who want more integration than apps like Miro provide.