OK show me faster.
I'm not sure I would need to. Your video shows EPG loading line-by-line (one HTTP request per channel). With XMLTV EPG, there is no real delay in loading. The entire guide is populated nearly instantly.
On another note, one of the benefits of XC/MAC is that it can request EPG data beyond the scope of what the XML has (think: last week, next week, etc). One idea to combat this is that the initial guide data could be populated instantly via XMLTV EPG, but then use the API when you start to come across parts of the guide that were not contained in the initial download. This hybrid approach could really be the best of both worlds. Would be a game changer for this box.