Could Dotmocracy replace Robert's Rules of Order i.e. debate and voting on motions?
Yes but not easily. The tradition and legal requirements of debating and voting on motions is over a century old in western governance systems. From student councils to town halls to organizational annual general meetings to national government assemblies, almost all follow a variation of Robert's Rules of Order. Trying to convince any organization that the standard way of doing democracy should be replaced requires a desire for change, organization wide education, and experience in successful application.
Specifically, the tradition of voting 'yay' or 'nay' on motions provides a simple and clear result of whether a proposal is approved by a majority or not. Rather than debating and the usual politicking in public assemblies and government process, Dotmocracy could be used as part of a more deliberative consensus process to generate a highly popular motion that is than formally approved by a vote.
Such a hybrid method could more likely fit within the legal requirements of many democratic organizations, although it would not satisfy those characters who desire competative debate (i.e. who would not be satisided with constructive deliberation) or those who are only interested in satisfying their 'clients' i.e. the power brokers that helped them get elected.