Is there a real point to using "Run as" local admin accounts instead of logging in as a local administrator?
The problem comes with these old-school developers. I'm afraid this will be turned into an office politics issue, since the loss of admin rights might come with a bit of productivity loss (especially for those who use privileges more often) and, more importantly, some frustration.
This isn't your battle to fight, so don't fight it. If people aren't happy about the change then tell them to speak to management.
Is the proposed change more secure? Yes. Does risk still exist in the new model? Yes. Is there less risk with the new model? Yes.
As an aside, I'd hate to be the person who quashed this and then find the company data and intellectual property ransomwared. And heaven forbid it makes it's way to client systems through your software. Ask the developers if they want that responsibility and accountability.