The current NFL overtime format is antiquated, unfair, and relies too much on chance and should be revamped. Ideally the the NFL should use the current college OT format, or a modified version of it, but the league is probably too old and stogy to admit that the college system is a good one.
History proves that the league doesn't like to use systems that are being used elsewhere. Proof of that lies in the leagues first attempt at video replay. The USFL system, which was basically what the current system is patterned after, was much better but the NFL decided on trying something different which eventually failed.
Back to what the league should do, at the least, with regard to OT. If they won't go the college route they should at least look into making two changes;
1) Get rid of the coin coss and give the 1st possession to the team that last played at least a full set of downs on defense.
2) Get rid of sudden death and allow each team at least one possession.