Agreed. I wish ITA had the Google Flights speed and interface for browsing multiple cities and dates but still allowed the advanced routing rules. Unfortunately, I doubt people like us doing MRs are their target audience.

Have they changed it? ITA used to be very popular with the FlyerTalk MR crowd. I used to use it for the searching flights stage (getting info but not booking).

I think the best matrix would be something like OAG, listing all flights that each airline is currently offering, but also listing prices on each flight.

A pipe dream if ever there was one.