Given that Kupu is Plone's default editor, and is probably likely to remain so for a while, I think it would be tremendous if OpenPlans invested its considerable energy and talent in identifying and fixing whatever warts Kupu has (and it certainly has them). I'm sure Duncan & the other Kupu maintainers would appreciate the help, and your efforts will have an immediate and massive benefit to the entire Plone community as well as to the OpenPlans suite.
OTOH, if you really think Kupu is problematic (and perhaps it is) then that's also a conversation that should really be taken out into the wider Plone community.
We won't be choosing Kupu, but we will be making a component for the editor of our choice to integrate into Plone, and adding some of the integration features that Kupu currently has to that editor.
As for the larger conversation, well... I hate asking communities to Make Big Plans For Change. We'll see how this goes for us, and what other people with different use cases think, and then when there's a concrete choice on the table we can revisit this question for the larger Plone community from a more informed position.# Ian Bicking