It does vary. Teams and/or subsets get there eventually, but not always. They seem very keen on completing their Defender version combiners, and they're two for two on that (and perhaps will soon hit three with Volcanicus). We have all three main Seekers in robot mode and in jet mode. Unicron's TFTM squad is complete. Sideswipe and Sunstreaker showed up together.
But it's taken us until now to even see another Datsunbro, the robot mode Constructicons need to start showing up (honestly I'm still burnt out on them, releasing both robot and vehicle modes so close together was not a good idea).
I'm a little curious as to how the headliners for later Defender series will go. They doubled up on Japanese BW in series 7, and now Battlestars. I guess there's still Headmasters and Masterforce. If they get around to Unicron Trilogy, that'll tie me up for dang sure.
But really what I want most right now is Defender version Mega Man. It's PERFECT for it, and the Champion class designs they've shown are looking great.