I've recently joined a team that has a good-sized website powered by Movable Type 4.25. Although my strengths are content strategy, information design and editing, I know just enough about Movable Type to know that WordPress is FAR superior. I've convinced the owner to convert the site to WordPress, but she questions whether it would even be possible to move everything. The disk space usage is 17558.43 MB. URL is soulbounce.com. I've tried to import posts/comments previously from blogs much smaller than this and had no success.
Considering the size of this, I wanted to ask any of you WordPress experts with experience converting a site from Movable Type to WordPress whether or not this would be a good idea. With Movable Type, the comments form crashes all the time, the site runs slow, there are theme limitations--all kinds of issues. Are there any special considerations or problems that we should be aware of with this type of conversion?
Thanks for any suggestions.