I find that waterfall comes with technical certainty. Waterfall is disastrous with erroneous technical certainty, if the customer is convinced that the solutio

I find that waterfall comes with technical certainty. Waterfall is disastrous with erroneous technical certainty, if the customer is convinced that the solution is technically clear and yet there is still uncertainty then what will happen is that a number of good components will be developed and delivered all of which are useless. If you can communicate (you must) the uncertainty and the potential branch points in your project then one of two things happens: - it stops (often) because the client does not have any appetite for risk. This is painful, but it is better than the car crash of a failed waterfall (which is what is going to happen). The opportunity cost for the team and you is very high here - kill it now and get something viable. - you go to agile and make it stick. As soon as you are certain about the solution the design is frozen and you can plan effectively for delivery. This is now waterfall and everyone is happy.