I think there will be more people looking to switch from MT. But my point of view is slightly different. Yes, many will be switching for the simple reason of getting something free, but there will be a lot of long-time MT users that are going to switch because they feel they've been burned. I for one feel that way and I switched just after MT 3.0 went into alpha.
For many MT users who have been faithfully using the software, the decision to limit features and usability that we've all grown used to is a slap in the face. Personally, I feel that 6A has decided the average blogger isn't as important as those that are commercial or personal business. They will bring in the money, so let's focus on pleasing them, but just for the hell of it, let's throw a bone to the "others" and give them a free version with half of what all previous versions of MT offered.
I think people are going to be offended and hurt by the neglect 6A has shown. Many people using MT simply cannot afford to purchase it, yet they've help and supported MT in other ways -- bringing more users, lending assistance in the forums, developing plugins. These people are the ones that will be switching to WordPress and other blogging software for reasons other than money. I don't think it is entirely about the actual cost of MT. It's the fact that they chose to please those that can afford it and cripple those who can't.
They could still have made money on MT, by extending the features in developer, but keeping existing features in the free. Plus they have Typepad (including Spain and France now) to bring them in money. That business ain't cheap either.