There is a big underlying philosopical problem behind all of this replay stuff: Many seem to think that with just the right system, that somehow every call will be right. It won't be. Perfection is an impossibility. The only real question is how much time, effort and expense do we want to expend to get better calls. I think the NFL system is junk due to the "challenge" mechanic. The system basically requires coaches to officiate the game at a cost of timeouts, but only for a select number of plays. In fact, the system actually double penalizes the teams that suffer the most bad calls because they simply can't fix them all. The best system for "fixing things" is probably continuous independant review of ALL decisions, but such a system has its own drawbacks and the costs (not just financial) may not feasible for baseball.