All fair points.
For one, you are correct about the Live TV support. One of the benefits of having such a large community is that we get a multitude of third-party plugins, scripts, skins, etc. That is also a problem in itself though, because they are often half-finished and poorly implemented. The MythTV frontend is such an example, though it has recently been picked up an greatly improved by our own dtierney.
The DVR rewrite is much more than that, it is an entire add-on framework that makes development more modular. It is being designed as a 'pvr-frontend' solution, one that you can hookup to one of many backends. There's no reason to rewrite what's already been done.
Your baby is ugly too! Really, though, the XBMC skinning engine is so powerful that simply diving in and changing a few things isn't exactly easy. That's also why we've drawn the interests of so many talented skinners and modders, the possibilities are endless. So it's a trade-off.
Currently Live TV certainly isn't what XBMC is known for, but it certainly excels as the face of your media library. We hope to improve that as time goes.
Sorry to hijack. Congratulations to the Myth devs on your release.