If we took a bit longer and waited for every feature that everyone held that opinion on ... well ... you'd be waiting even longer than it took Nokia to deliver a software update

Moving on (though I hope you get the point I'm trying to make, humour aside) - work on CalDAV is proceeding (https://github.com/nemomobile/buteo-sync-plugin-caldav/) - but it won't be featured in the next update. It probably won't be too far off, though, given it's coming together (YMMV: I don't work on any of this stuff, I haven't looked at the actual plans, just recalling what I remember).

It's taken a bit longer than I personally expected it would, but there's been a pretty big pile of work on top of the guys working on it, so I'm not entirely surprised.