ergophobe - 5:25 am on Aug 22, 2012 (gmt 0)
I just don't think that collecting, slicing and dicing complex structured data is in the bones of Wordpress and you'll always have to "make" it do you want. With Drupal + Views, it just does what you want. That said, Drupal has traditionally been a more abstract system - a framework really - and say meta titles, h1s, URLs, menu titles, etc don't necessarily have a defined relationship until you define it. This is now better in WP, but one of my big stumbling blocks there was the lack of abstraction.
Joomla... I've never really seen the value. I think these days, if Joomla can do it, so can WP. If you're going to bump up in complexity, might as well bump to Drupal which can really do things others just can't, at least not naturally and not in a logical way in the underlying database schema (at least in my experience).
On the second point (mobile), I would have to agree that the downside to a responsive design is that it hides cruft, but it still transfers it. So at low data speeds, you still pay that penalty.