In my opinion, I think that if they were to replace DC with a coaster; it'd be from Mack. They are highly reliable, there are a variety of coaster types to choose from them that'd be a Orlando first and that they are quite a bit enjoyable for what they are.
An Inverted Power Coaster in particular; is one I think will be seen in Orlando in the future, but I would suspect Universal wanting to use that. It leads to a lot of potential, and perhaps with working with Mack and an external party; they could have the arms be capable to do more than just rotating on the axis, to further enhance the technology one step ahead of anything else in the industry.