My Workflow for sync with tempo and time signature shifts

It was discussed here earlier that using rewire in conjunction with tempo changes pretty much breaks audio functionality in every sequencer. The is due to the fact that the sequencer is unaware of the tempo changes that had come before it. It sees the current BPM as the only BPM in the project.

As far as I understand this is not Synfires doing. This is just rewire in action, though I'm not sure why there hasn't been a general outcry before? Perhaps tempo changes aren't the Rewire crowds modus operandi?

I've been experimenting with a number of ways to get sync with the corresponding tempo changes in the host. This effects not only audio editing but also any effects or synths that use the BPM for delays ARPS etc...

Fairly simple, but the best work around seems to be to use MTC and then import an empty midi file with just the tempo track into the sequencer. I find MTC to be "good enough" and the luxury of being able to edit audio and have beat synced sounds is well worth it.

I found the using rewire along with a DAW tempo map does not work in the same way.

If the MTC + Tempo Map method is deemed to be the most reasonable workflow, I have a simple idea that would aid greatly in making quick adjustments to the tempo.

The feature would add the ability to drag the tempo parameter, as you would drag any other parameter in Synfire, directly into the DAW sequencer.

Behind the scenes synfire would create a temporary midi file in the Synfire projects' directory with just the tempo and signature information and no leadin. It would then add that file to the sequencer (just in the same way you can drag and drop files in most applications.)

Snyfire could then potentially delete the tempo file, as most sequencers I know of don't reference the original midi file past the initial import.

With this method, the tempo map can be adjusted in the DAW to match the changes in Synfire with one quick gesture.