The final 12 spots in the draft go to playoff teams in reverse order of finish, then teams are ranked by record. After that:
Divisional and conference tie-breakers are sufficient to ensure that there are no ties within a conference, but if the 2 teams in question are from different conferences, then we have a problem. There is only 1 tie-breaker in that situation, strength of schedule. This year there were 2 different ties between inter-conference teams that required a coin flip (Dolphins/Panthers for 8/9, Dolphins won. Chiefs/Seahawks for 11/12, Chiefs won).ties shall be broken by strength-of-schedule. If any ties cannot be broken by strength-of-schedule, the divisional or conference tie-breakers, if applicable, shall be applied. Any ties that still exist shall be broken by a coin flip.
This has happened with no controversy, the NFL even made special coins to avoid a Bettis-like scenario. But that's because the picks were all in the 8-12 range. Can the NFL really be so blissfully unaware of the fact that if this system is left unchanged we will eventually have a coin toss for the #1 overall pick? If and when that occurs there will be lots of negative publicity pointing out the league's lack of foresight. The league will then promise that it will never happen again and change the rules. Why not change them now and stop it from happening the first time? Why not just apply the conference tie-breakers league wide? It's not a perfect solution, those tie-breakers were specifically designed for in-conference use, but it's better than a coin toss.