Looking for opinions, legal or otherwise, regarding the impact of the forthcoming ruling in this case. What are the implications and ramifications to business?
What reactions might be expected in response either way the case is decided?

Based on what I read about the oral argument -- and about the fact that in a similar case (Lockheed v. Spink), the Supreme Court reversed the Ninth Circuit 9-0 -- there's a pretty good chance the Ninth Circuit's opinion in Hughes will be overturned. That just means business as usual -- plan sponsors will be free to merge DB plans, including contributory and noncontributory plans, and then to amend the merged plan to provide different or special benefits to specific subgroups or classes of participants, without fear that doing so would trigger a "termination" of the plan or a portion of it.
This is and would remain a sponsor's best option for "using" pension plan surplus assets (which cannot revert directly to the employer without confiscatory income and excise taxes).