FWIW, I just did a quick scan of school scheduling models, and apparently variations of this have been tried over the past 50 years or so, with stakeholder feedback running across the whole spectrum. I expect success depends a great deal on implementation. It appears to be a synthesis of a few models: the 75/75/30 plan (hence two long trimesters and one short semester, with core courses loaded in early trimesters), and a full-day-class rotating or alternating schedule.
So it's all been done before somewhere. The research I could find on the effect of schedules on achievement pretty much finds -- big surprise -- that it depends more on the teachers and what they do with the time than on the structure of the schedule itself. IOW, it seems likely that your school will be as effective with this schedule as would be predicted from how this set of faculty was under the old schedule. The good teachers will use the opportunity to go deep and use a variety of interactive and creative teaching methods, and probably enjoy having more latitude. The mediocre teachers will adjust their plans to do five or six lightly-modified lessons a day. The weak teachers will be just as ineffective, which will probably make two days a week particularly painful for their students...but they won't have to see them the rest of the time.
