Yeah, Ardour definitely started life as linear/timeline recording tool, along the lines of (then) ProTools/Samplitude/Pyramix/Sequoia.
Ableton Live changed everything, even for the sequencer-originated DAWs like Cubase, and it's true that in Ardour we haven't (yet) attempted to tackle that sort of thing.
Personally I prefer the lack of a sequencer in ardour. I use muse or rosegarden for most midi tracks and hydrogen for drums. I feel like this fits more with the modular linux philosophy, though I do realize ardour is cross platform. I appreciate that ardour has pretty much one paradigm and does it well.
Ableton Live changed everything, even for the sequencer-originated DAWs like Cubase, and it's true that in Ardour we haven't (yet) attempted to tackle that sort of thing.
Stay tuned though!