I think that once it is accepted that the CX platform is a true Morgan (the opinion has already softened over the past year) there will be a good number of trad owners switching over, similar to the Aero being generally more accepted as time went on, superformed wings, and so on..
Of course some will want to keep their traditional cars, either for experience, fondness, cost or a raft of other reasons. This is what makes Morgan great at the moment, there is something for every Morgan enthusiast and I think the Plus Four will be a great success.
All I hope is that they release a 4/4 entry model with less power and a lower price, which will help attract those that might not otherwise have bought into the brand. I have read countless tales of 4/4 owners purchasing based on the competitive price (a few years ago now) and then seemingly upgrading to more expensive cars later on.
Certainly with the immense performance of the Plus 4, I think a slower 4/4 is needed!