It's been discussed before. It sounds great and there are people on here who have all the technical information for exactly how it could work. However, there isn't any indication for that happening in the near future.
Personally, I'm fine with the way it is now. There are some tangibles that do need to be communicated with a Disney Cast Member. A larger party that will need two tables, special diet considerations, dress codes, seating (like eight at the Biergarten). If the system was automated, these would have to be addressed and if someone has one of these issues and doesn't realize it, they are going to be very surprised and possibly disappointed when they go for their meal. I don't think any of us actually read the agreements when we sign up for anything online. We just click "I agree" and go.