Nothing simpler about the TH350 other than you have to set up the TV cable correctly on the 700r4. TH350 controls shifts with a vacuum modulator, 700 uses a throttle valve which controls line pressure and shift points to a degree. The TV cable has to be set correctly otherwise the trans will burn up, but there is plenty of information out there to get it right the first time.
As insurance I put a will put a pressure gauge on the 700r4 and check line pressures before it leaves the garage just to verify all is right.
Another benefit of the 700 is the lockup converter, I have mine set to lock when shifting into 4th gear. Drops the RPM a couple hundred more for even better mileage.