I would answer no to that question. I would answer that question by pointing out that large LCDs also require more space and larger batteries. However, I predict better, smaller LCDs to be used instead, and color would not hurt if it can be done efficiently. However, the only thing the screen would even be used for is basic functions, such as viewing a phone number, or setting phone functions. Sure, this could probably be done using voice recognition, but I am sure I would get tired of talking to my PDA all the time.
Alternatives are essential.
So far we have covered regular PDA functions, phone functions, Internet capabilities, voice recognition, and the LCD screen. Super thin, foldable headphones can remedy this problem. Also, a microphone should also be added in for more accurate voice recognition for use in a car or other possibly noisy environments. Now, let me get away from voice recognition and also contradict myself on the LCD design. I believe there will be a smaller market for PDAs with bigger, better LCDs for highly advanced functions.