What I meant by "the whole org is on board" isn't that there weren't other opinions. There have been multiple opinions on almost every decision we make (and we have an open process and document our decisions in a style very much like this one[1]). In the end, it's not about "shooting down" alternatives, since that's loaded language. It's about making what we think is the best choice we can with the information available to us.
Even in this thread, there's a chorus of voices sounding caution based on their limited information of what our situation looks like, but there are others who see why we're doing this, based on the same limited information.
We absolutely do know the risks of this project, which is why we're doing this as incrementally as possible.
[1]: http://thinkrelevance.com/blog/2011/11/15/documenting-archit...