MO schools obviously have their own drawbacks: hashkafa (although, not all are left-wing) but most important – kid environment. Frankly also for those who pay close to full tuition, the prices are ridiculous because they are trying to provide all kind of options and entertainment. You are better of hiring a full-time PhD tutor for the tuition for 2-3 kids. Probably two part-timers, one for math, one for English
Practically speaking, I think, it is possible to have quality general studies in a yeshivishe school. Your biggest challenge would be that many families are not interested, and so do principals. Try finding a couple of other families interested in higher quality studies, talk school into letting them do this extra program, or go home for those hours. Use online curriculum and old-fashioned books.
Also there are several yeshivos and BYs that even successfully integrated online public schools into their day. I think, a yeshiva in LA sends kids to a separate floor where they have computers for general studies, and then they come back to a normal yeshiva floor. See Avi Chai foundation site – they sponsored several schools on doing this “blended” approach and have reports with all details.