Displays were primarily used to inform the player of their score. Woodrails had lit areas on the backglass and then we went to reels and the BIG change to digital displays. I remember when the first SS Evel Knievel was unboxed. The "horror" of a digital display and the fear that it would be problematic. Older technicians dreaded them because they didn;t understand them. But this was the biggest change when the industry was in it's "Golden Years". It eventually took off and then we moved to alphanumeric and then the DMD.
I seldom look at a display unless I'm chasing an opponent's score, or, the high score. I don't like "Video modes". I love the interaction on the playfield. CV is the perfect example of what I like about DMDs.
Having said that, I love the colour DMDs. It completely changes the visual presentation of the game. As other's have mentioned, it is an AWESOME sight when waiting for a player to finish his ball.
The change from EMs to SS did change the industry, and the strongest years quickly followed. So something like a change to a standard DMD has the capacity to be a very positive change, but I don't think it is vital because all manufacturer's realize that the target customer base is mostly collectors.
That's where the full size LCDs (Like JJP) will fail. The fundamental idea of pinball is to follow a ball around a playfield. It I want to watch cutscenes from the movies, I'll watch it on TV, not on the pinball.
ColourDMD has the potential to revitalize existing machines in collections. It is not exactly an innovation, but an enhancement. It is the best enhancement to pinball in the last 10 years.
If "Walking Dead" had a colourDMD, I'd almost consider buying it. I'd never buy a JJP because the screen is a deterrent.