This is a good point. I agree that having a 2 hour slot doesn't guarantee that I will get into a flow state, but it is a prerequisite for me to have a couple of hours at least to do this type of work.

I think the idea of being able to loosely schedule certain meetings (eg "Give me the least worst 30 minutes for the 3 people this week") could be an interesting thing to try. Having a system which knows whether it is advisable to 'bring forward' or 'push back' a meeting could be a big help. I also think that if a meeting is continually pushed back or brought forward, this might be interesting information in and of itself, especially for recurring meetings.

There could be downsides to this and I find it hard to even imagine what such a system would be like, given my current experience with Google Calendar, where even scheduling a meeting or room seems to be about 5 minute process.