I'm not sure stopping the practice of redshirting will do much for you. Certainly won't do anything if there is a player or multiple ahead of a kid. I think most freshman that can contribute do see the field, don't they? Obviously that is position dependent but true phenoms that can play off the HS bus usually do.
As for that second component, it's always one I've wrestled with and your viewpoint rests on whether you view college as a football factory or educational institution. On one hand, letting players hit the market on a coaching change will likely cause a very volatile market where you'll see even more kids cut because the grass is always greener. On the other hand, it may also influence some stability because schools won't want their teams gutted if they decide to fire a coach. However, if a coach leaves to "take a better job" is it fair to the school that has invested hundreds of thousands (some programs in the millions) of dollars into their student-athletes to have them show no loyalty to the school?