Esquire, Joex444 and WyomingKnott all make very interesting points.
If we were to consider the analogy of the buffet, it makes perfect sense that if we all pay the same price but eat a different amount, no-one complains that one person ate more than another, it's all the point of the buffet. If we look back on the days of dial-up popularity, it was no different where some used dial-up constantly whereas some didn't use it much at all. Why not keep the "all you can use" option if people are willing to pay for that freedom, and are going to use it? I for one do use significant bandwidth daily.
Joex444 made an excellent suggestion of offering the tiered levels on top of the current structure. why not keep what people already use, but give additional options for lighter usage persons? You keep the base that already enjoys the service you have, and adopt a larger customer group with more options, not less. I have many family who would love such an option of fast internet but in limited usage amounts while others would go for the "full monty".
And last (but not least) WyomingKnott makes a valid statement about the fact that this is a business, and as such they are trying to turn a profit as well as maintain a highly reliable and costly service. At the same time I respectfully disagree that we should pay for "what we use". If that is the case, then why am I paying for cable capability that was run to households who chose to buy satellite, U-verse, or rabbit ears? Does that mean the cable company owes me a refund for what I paid for and is not in use by me? It is the company's choice, and as such they chose this model of business, and yet need to remain competitively priced.
I feel the flat rate unlimited use model is not only enjoyed by many, it's expected by many as well. Just like unlimited models of cell phone texting and other services, business competition will cause someone to continue an internet unlimited model. I hope T.W. will consider this for the sake of their business.