To answer your question, yes, there would be a successor plan - and the issue is as Tom points out - the establishment of a successor plan (withing the 24 month period beginning 12 months before the plan termination and ending 12 months after) would mean there would not be a "distributeable event" from the terminated plan for any of it's participants.
That would leave two options - 1) maintain the existing plan (and any evil it contains - which in my mind would be the only reason to consider it's termination); or 2) merge the plan into the new one (which would merge the evil into the new plan, tainting it). Now, you arguably could give participants the option of leaving balances in the old plan or "rolling over" to the new plan (but not taking a distribution), but in effect, that is a "partial" merger of assets which a good lawyer could/would argue taints the new plan as much as a complete merger.
My recommendation: If there is a problem with the existing plan - FIX IT. Everything can be fixed - the only variable is the time and money it takes - but IF ITS BROKEN, IT NEEDS TO BE FIXED.
Then, don't worry about "termination" and new plan set up and successor plan issues....