Look, Deathwatcher still goes for 40+ US$ on eBay. I traded my extra for an epic. And it's a terrible, unplayable mini. You have to take into account that it doesn't cost 25$ to get one. It costs 25$ plus hotel and airfare.
Mortimer is very playable, and I know a bunch of us DMF top 8 players are trying to get three of him (thus reducing further the amount available on the market). On the flipside, it's likely to be out there in more copies than the Deathwatcher. So it's hard to tell right now how much it's gonna be. I think it's gonna be real high right after Boston, and drop a bit down in price after each DMF.
"The beatings will continue until morale has improved."
- Standard corporate management technique