Over the past two years, the league has used a combination of focus groups, market research, situational NFL data, in-game testing and conversations with coaches, players and other experts to shape what XFL commissioner Oliver Luck believes will be a faster, more exciting brand of professional football.

Many of those ideas fizzled quickly, upon the realization that they would fundamentally alter the nature of the sport. Other possible rule changes — like the halo rule that the Canadian Football League has implemented on punt returns — made it further in the process but also did not make the final cut.
Dean Blandino, the XFL's head of officiating, said he thinks the most consequential rule change will be the implementation of a 25-second play clock. (The NFL's play clock is 40 seconds.) The rule is largely designed to speed up games and keep them within a three-hour window; the league's research showed that the average NFL game has nearly 17 minutes of inaction, in real time, after incompletions.
"At least at first glance, you go 'whoa, 25 seconds, that’s pretty quick,'" Blandino said. "But when you talk about OK, we have a dedicated ball-spotter. We have some built-in time between when the ball-spotter’s going to get the ball at the end of the down and put it down and wind the clock. It really started to make a lot of sense."