I've been to three different Touhou panels, each with their different approaches.
The Anime North panel hosted by Gpop and company was amazing despite the limited time and space set aside for it. There really wasn't much of an introduction, it was pretty much all discussion; talking about the games released in the previous year (which at the time were GFW and the 10D demo), recent events in the fandom, and speculation. It was pretty fun, and afterward we 'borrowed' an unused room for showing off games and merchandise to each other.
The Animethon Touhou panel prior to 2012 was... disappointing. The host was trying to introduce the series, but he was... very lacking in knowledge about the series. He would generally show off one game and a few videos, although as an introduction it seemed... very uninteresting.
The Touhou panel at Animethon 2012 and onward was generally agreed by people to be a better improvement. The new host had a vastly different style, being quite knowledgeable about the franchise and regularly asking questions to make sure even longtime fans were kept engaged. I liked it, and honestly went to the con just to see this panel.